Method for executing power control and user equipment

ABSTRACT

A disclosure of the present specification provides a method for executing power control by a user equipment (UE). The method may include the steps of: determining a first amount of power for transmitting a first uplink control information (UCI) by a user equipment (UE) set to have a dual connectivity with a first cell group and a second cell group; and determining a second amount of power for transmitting a second UCI. Herein, when the first UCI includes HARQ-ACK but the second UCI does not include HARQ-ACK, the determination of the first amount of power may have a priority over the determination of the second amount of power.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.16/007,379, filed on Jun. 13, 2018, now allowed, which claims thebenefit of U.S. application Ser. No. 15/300,671, filed on Sep. 29, 2016,now U.S. Pat. No. 10,028,230, which is a National Stage Filing under 35U.S.C. 371 of International Application No. PCT/KR2015/001075, filed onFeb. 2, 2015, which claims the benefit of U.S. Provisional Nos.61/977,109, filed on Apr. 9, 2014, 61/984,003, filed on Apr. 24, 2014,62/004,222, filed on May 29, 2014, 62/055,633, filed on Sep. 25, 2014and 62/060,589, filed on Oct. 7, 2014. The disclosures of the priorapplications are incorporated by reference in their entirety.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to mobile communication.

Related Art

3rd generation partnership project (3GPP) long term evolution (LTE)evolved from a universal mobile telecommunications system (UMTS) isintroduced as the 3GPP release 8. The 3GPP LTE uses orthogonal frequencydivision multiple access (OFDMA) in a downlink, and uses singlecarrier-frequency division multiple access (SC-FDMA) in an uplink.

Such LTE may be divided into a frequency division duplex (FDD) type anda time division duplex (TDD) type.

As set forth in 3GPP TS 36.211 V10.4.0, the physical channels in 3GPPLTE may be classified into data channels such as PDSCH (physicaldownlink shared channel) and PUSCH (physical uplink shared channel) andcontrol channels such as PDCCH (physical downlink control channel),PCFICH (physical control format indicator channel), PHICH (physicalhybrid-ARQ indicator channel) and PUCCH (physical uplink controlchannel).

Meanwhile, in order to process a growing number of data, in anext-generation mobile communication system, a small cell having a smallcell coverage radius is anticipated to be added to coverage of anexisting cell and process more traffic.

On the other hand, the UE may be dually connected to the macro cell andthe small cell.

However, the power control method of the terminal considering the dualconnection situation has not yet been researched.

SUMMARY OF THE INVENTION

Accordingly, a disclosure of the present specification has been made inan effort to solve the aforementioned problem.

To achieve the aforementioned purposes of the present invention, onedisclosure of the present specification provides a method for performinga power control. The method may performed by a user equipment (UE) andcomprise: determining, by the UE configured with dual connectivity to afirst cell group and a second cell group, first amount of power for atransmission of a first UCI; and determining second amount of power fora transmission of a second UCI. If the first UCI includes HARQ-ACK andif the second UCI does not include HARQ-ACK, the determination of thefirst amount of the power is prioritized over the determination of thesecond amount of the power.

If the first UCI includes HARQ-ACK to the first cell group and if thesecond UCI include HARQ-ACK to the second cell group, the determinationof the first amount of the power may be prioritized over thedetermination of the second amount of the power.

The method may further comprise: scaling down the first amount of thepower if the first amount of the power exceeds a specific value.

In the determinations, a first guaranteed power for a first eNodeB and asecond guaranteed power for a second eNodeB may be considered.

The method may further comprise: receiving information on the firstguaranteed power and the second guaranteed power

The first guaranteed power may be expressed as P_MeNB and the secondguaranteed power may be expressed as P-SeNB

The determinations may be performed if a first subframe on which thefirst UCI is transmitted to a first cell group is overlapped with asecond subframe on which the second UCI is transmitted to a second cellgroup.

To achieve the aforementioned purposes of the present invention, onedisclosure of the present specification provides a user equipment (UE)for performing a power control. The UE may comprise: a radio frequency(RF) unit; and a processor configured to determine first amount of powerfor a transmission of a first UCI and second amount of power for atransmission of a second UCI if a dual connectivity to a first cellgroup and a second cell group is configured through the RF unit. Here,if the first UCI includes HARQ-ACK and if the second UCI does notinclude HARQ-ACK, the determination of the first amount of the power isprioritized over the determination of the second amount of the power.

To achieve the aforementioned purposes of the present invention, onedisclosure of the present specification also provides a method forperforming a power control. The method may be performed by a userequipment (UE) and comprise: determining, by the UE configured with dualconnectivity to a first cell group and a second cell group, first amountof transmission power toward the first cell group. Here, if a firstsubframe for a transmission to the first cell group is overlapped with asecond subframe for a transmission to the second cell group, and if thefirst frame is used to transmit a sounding reference signal (SRS), apower for transmitting the SRS is prioritized in the determination.

According to a disclosure of the present invention, the above problem ofthe related art is solved.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a wireless communication system.

FIG. 2 illustrates the architecture of a radio frame according tofrequency division duplex (FDD) of 3rd generation partnership project(3GPP) long term evolution (LTE).

FIG. 3 illustrates an example resource grid for one uplink or downlinkslot in 3GPP LTE.

FIG. 4 illustrates the architecture of a downlink subframe.

FIG. 5 illustrates the architecture of an uplink subframe in 3GPP LTE.

FIG. 6a illustrates one example of periodic CSI reporting in 3GPP LTE.

FIG. 6b illustrates one example of aperiodic CSI reporting in the 3GPPLTE.

FIG. 6c illustrates one example of simultaneous transmission of PUCCHand PUSCH.

FIG. 7 illustrates the PUCCH and the PUSCH on an uplink subframe.

FIG. 8 is a diagram illustrating an environment of heterogeneousnetworks of a macro cell and a small cell which may become anext-generation wireless communication system.

FIGS. 9a and 9b illustrate scenarios of dual connectivity possible withrespect to the macro cell and the small cell.

FIG. 10 is an exemplary diagram illustrating one method according to afirst disclosure of the present specification.

FIGS. 11a to 11e illustrate one example for power control in a situationin which subframes are asynchronous among eNodeBs.

FIG. 12 is a flowchart of a summarized disclosures of the presentspecification.

FIG. 13 is a block diagram illustrating a wireless communication systemin which the disclosures of the present specification is implemented.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

Hereinafter, based on 3rd Generation Partnership Project (3GPP) longterm evolution (LTE) or 3GPP LTE-advanced (LTE-A), the present inventionwill be applied. This is just an example, and the present invention maybe applied to various wireless communication systems. Hereinafter, LTEincludes LTE and/or LTE-A.

The technical terms used herein are used to merely describe specificembodiments and should not be construed as limiting the presentinvention. Further, the technical terms used herein should be, unlessdefined otherwise, interpreted as having meanings generally understoodby those skilled in the art but not too broadly or too narrowly.Further, the technical terms used herein, which are determined not toexactly represent the spirit of the invention, should be replaced by orunderstood by such technical terms as being able to be exactlyunderstood by those skilled in the art. Further, the general terms usedherein should be interpreted in the context as defined in thedictionary, but not in an excessively narrowed manner.

The expression of the singular number in the specification includes themeaning of the plural number unless the meaning of the singular numberis definitely different from that of the plural number in the context.In the following description, the term ‘include’ or ‘have’ may representthe existence of a feature, a number, a step, an operation, a component,a part or the combination thereof described in the specification, andmay not exclude the existence or addition of another feature, anothernumber, another step, another operation, another component, another partor the combination thereof.

The terms ‘first’ and ‘second’ are used for the purpose of explanationabout various components, and the components are not limited to theterms ‘first’ and ‘second’. The terms ‘first’ and ‘second’ are only usedto distinguish one component from another component. For example, afirst component may be named as a second component without deviatingfrom the scope of the present invention.

It will be understood that when an element or layer is referred to asbeing “connected to” or “coupled to” another element or layer, it can bedirectly connected or coupled to the other element or layer orintervening elements or layers may be present. In contrast, when anelement is referred to as being “directly connected to” or “directlycoupled to” another element or layer, there are no intervening elementsor layers present.

Hereinafter, embodiments of the present invention will be described ingreater detail with reference to the accompanying drawings. Indescribing the present invention, for ease of understanding, the samereference numerals are used to denote the same components throughout thedrawings, and repetitive description on the same components will beomitted. Detailed description on well-known arts which are determined tomake the gist of the invention unclear will be omitted. The accompanyingdrawings are provided to merely make the spirit of the invention readilyunderstood, but not should be intended to be limiting of the invention.It should be understood that the spirit of the invention may be expandedto its modifications, replacements or equivalents in addition to what isshown in the drawings.

As used herein, ‘base station’ generally refers to a fixed station thatcommunicates with a wireless device and may be denoted by other termssuch as eNB (evolved-NodeB), BTS (base transceiver system), or accesspoint.

As used herein, user equipment (UE) may be stationary or mobile, and maybe denoted by other terms such as device, wireless device, terminal, MS(mobile station), UT (user terminal), SS (subscriber station), MT(mobile terminal) and etc.

Referring to FIG. 1, the wireless communication system includes at leastone base station (BS) 20. Respective BSs 20 provide a communicationservice to particular geographical areas 20 a, 20 b, and 20 c (which aregenerally called cells).

The UE generally belongs to one cell and the cell to which the terminalbelong is referred to as a serving cell. A base station that providesthe communication service to the serving cell is referred to as aserving BS. Since the wireless communication system is a cellularsystem, another cell that neighbors to the serving cell is present.Another cell which neighbors to the serving cell is referred to aneighbor cell. A base station that provides the communication service tothe neighbor cell is referred to as a neighbor BS. The serving cell andthe neighbor cell are relatively decided based on the UE.

Hereinafter, a downlink means communication from the base station 20 tothe terminal 10 and an uplink means communication from the terminal 10to the base station 20. In the downlink, a transmitter may be a part ofthe base station 20 and a receiver may be a part of the terminal 10. Inthe uplink, the transmitter may be a part of the terminal 10 and thereceiver may be a part of the base station 20.

Hereinafter, the LTE system will be described in detail.

FIG. 2 shows a downlink radio frame structure according to FDD of 3rdgeneration partnership project (3GPP) long term evolution (LTE).

The radio frame of FIG. 2 may be found in the section 5 of 3GPP TS36.211 V10.4.0 (2011-12) “Evolved Universal Terrestrial Radio Access(E-UTRA); Physical Channels and Modulation (Release 10)”.

Referring to FIG. 2, the radio frame consists of 10 subframes. Onesubframe consists of two slots. Slots included in the radio frame arenumbered with slot numbers 0 to 19. A time required to transmit onesubframe is defined as a transmission time interval (TTI). The TTI maybe a scheduling unit for data transmission. For example, one radio framemay have a length of 10 milliseconds (ms), one subframe may have alength of 1 ms, and one slot may have a length of 0.5 ms.

The structure of the radio frame is for exemplary purposes only, andthus the number of subframes included in the radio frame or the numberof slots included in the subframe may change variously.

Meanwhile, one slot may include a plurality of OFDM symbols. The numberof OFDM symbols included in one slot may vary depending on a cyclicprefix (CP).

FIG. 3 illustrates an example resource grid for one uplink or downlinkslot in 3GPP LTE.

Referring to FIG. 3, the uplink slot includes a plurality of OFDM(orthogonal frequency division multiplexing) symbols in the time domainand NRB resource blocks (RBs) in the frequency domain. For example, inthe LTE system, the number of resource blocks (RBs), i.e., NRB, may beone from 6 to 110.

Resource block (RB) is a resource allocation unit and includes aplurality of sub-carriers in one slot. For example, if one slot includesseven OFDM symbols in the time domain and the resource block includes 12sub-carriers in the frequency domain, one resource block may include7×12 resource elements (REs).

Meanwhile, the number of sub-carriers in one OFDM symbol may be one of128, 256, 512, 1024, 1536, and 2048.

In 3GPP LTE, the resource grid for one uplink slot shown in FIG. 4 mayalso apply to the resource grid for the downlink slot.

FIG. 4 illustrates the architecture of a downlink sub-frame.

In FIG. 4, assuming the normal CP, one slot includes seven OFDM symbols,by way of example.

The DL (downlink) sub-frame is split into a control region and a dataregion in the time domain. The control region includes up to first threeOFDM symbols in the first slot of the sub-frame. However, the number ofOFDM symbols included in the control region may be changed. A PDCCH(physical downlink control channel) and other control channels areallocated to the control region, and a PDSCH is allocated to the dataregion.

The physical channels in 3GPP LTE may be classified into data channelssuch as PDSCH (physical downlink shared channel) and PUSCH (physicaluplink shared channel) and control channels such as PDCCH (physicaldownlink control channel), PCFICH (physical control format indicatorchannel), PHICH (physical hybrid-ARQ indicator channel) and PUCCH(physical uplink control channel).

The PCFICH transmitted in the first OFDM symbol of the sub-frame carriesCIF (control format indicator) regarding the number (i.e., size of thecontrol region) of OFDM symbols used for transmission of controlchannels in the sub-frame. The wireless device first receives the CIF onthe PCFICH and then monitors the PDCCH.

Unlike the PDCCH, the PCFICH is transmitted through a fixed PCFICHresource in the sub-frame without using blind decoding. The PHICHcarries an ACK (positive-acknowledgement)/NACK(negative-acknowledgement) signal for a UL HARQ (hybrid automatic repeatrequest). The ACK/NACK signal for UL (uplink) data on the PUSCHtransmitted by the wireless device is sent on the PHICH.

The PBCH (physical broadcast channel) is transmitted in the first fourOFDM symbols in the second slot of the first sub-frame of the radioframe. The PBCH carries system information necessary for the wirelessdevice to communicate with the base station, and the system informationtransmitted through the PBCH is denoted MIB (master information block).In comparison, system information transmitted on the PDSCH indicated bythe PDCCH is denoted SIB (system information block).

The PDCCH may carry activation of VoIP (voice over internet protocol)and a set of transmission power control commands for individual UEs insome UE group, resource allocation of an upper layer control messagesuch as a random access response transmitted on the PDSCH, systeminformation on DL-SCH, paging information on PCH, resource allocationinformation of UL-SCH (uplink shared channel), and resource allocationand transmission format of DL-SCH (downlink-shared channel). A pluralityof PDCCHs may be sent in the control region, and the terminal maymonitor the plurality of PDCCHs. The PDCCH is transmitted on one CCE(control channel element) or aggregation of some consecutive CCEs. TheCCE is a logical allocation unit used for providing a coding rate perradio channel's state to the PDCCH. The CCE corresponds to a pluralityof resource element groups. Depending on the relationship between thenumber of CCEs and coding rates provided by the CCEs, the format of thePDCCH and the possible number of PDCCHs are determined.

The control information transmitted through the PDCCH is denoteddownlink control information (DCI). The DCI may include resourceallocation of PDSCH (this is also referred to as DL (downlink) grant),resource allocation of PUSCH (this is also referred to as UL (uplink)grant), a set of transmission power control commands for individual UEsin some UE group, and/or activation of VoIP (Voice over InternetProtocol).

The base station determines a PDCCH format according to the DCI to besent to the terminal and adds a CRC (cyclic redundancy check) to controlinformation. The CRC is masked with a unique identifier (RNTI; radionetwork temporary identifier) depending on the owner or purpose of thePDCCH. In case the PDCCH is for a specific terminal, the terminal'sunique identifier, such as C-RNTI (cell-RNTI), may be masked to the CRC.Or, if the PDCCH is for a paging message, a paging indicator, forexample, P-RNTI (paging-RNTI) may be masked to the CRC. If the PDCCH isfor a system information block (SIB), a system information identifier,SI-RNTI (system information-RNTI), may be masked to the CRC. In order toindicate a random access response that is a response to the terminal'stransmission of a random access preamble, an RA-RNTI (randomaccess-RNTI) may be masked to the CRC.

In 3GPP LTE, blind decoding is used for detecting a PDCCH. The blinddecoding is a scheme of identifying whether a PDCCH is its own controlchannel by demasking a desired identifier to the CRC (cyclic redundancycheck) of a received PDCCH (this is referred to as candidate PDCCH) andchecking a CRC error. The base station determines a PDCCH formataccording to the DCI to be sent to the wireless device, then adds a CRCto the DCI, and masks a unique identifier (this is referred to as RNTI(radio network temporary identifier) to the CRC depending on the owneror purpose of the PDCCH.

The uplink channels include a PUSCH, a PUCCH, an SRS (Sounding ReferenceSignal), and a PRACH (physical random access channel).

FIG. 5 illustrates the architecture of an uplink sub-frame in 3GPP LTE.

Referring to FIG. 5, the uplink sub-frame may be separated into acontrol region and a data region in the frequency domain. The controlregion is assigned a PUCCH (physical uplink control channel) fortransmission of uplink control information. The data region is assigneda PUSCH (physical uplink shared channel) for transmission of data (insome cases, control information may also be transmitted).

The PUCCH for one terminal is assigned in resource block (RB) pair inthe sub-frame. The resource blocks in the resource block pair take updifferent sub-carriers in each of the first and second slots. Thefrequency occupied by the resource blocks in the resource block pairassigned to the PUCCH is varied with respect to a slot boundary. This isreferred to as the RB pair assigned to the PUCCH having beenfrequency-hopped at the slot boundary.

The terminal may obtain a frequency diversity gain by transmittinguplink control information through different sub-carriers over time. mis a location index that indicates a logical frequency domain locationof a resource block pair assigned to the PUCCH in the sub-frame.

The uplink control information transmitted on the PUCCH includes an HARQ(hybrid automatic repeat request), an ACK (acknowledgement)/NACK(non-acknowledgement), a CQI (channel quality indicator) indicating adownlink channel state, and an SR (scheduling request) that is an uplinkradio resource allocation request.

The PUSCH is mapped with a UL-SCH that is a transport channel. Theuplink data transmitted on the PUSCH may be a transport block that is adata block for the UL-SCH transmitted for the TTI. The transport blockmay be user information. Or, the uplink data may be multiplexed data.The multiplexed data may be data obtained by multiplexing the transportblock for the UL-SCH and control information. For example, the controlinformation multiplexed with the data may include a CQI, a PMI(precoding matrix indicator), an HARQ, and an RI (rank indicator) Or,the uplink data may consist only of control information.

<Carrier Aggregation: CA>

Hereinafter, a carrier aggregation system will be described.

The carrier aggregation (CA) system means aggregating multiple componentcarriers (CCs). By the carrier aggregation, the existing meaning of thecell is changed. According to the carrier aggregation, the cell may meana combination of a downlink component carrier and an uplink componentcarrier or a single downlink component carrier.

Further, in the carrier aggregation, the cell may be divided into aprimary cell, secondary cell, and a serving cell. The primary cell meansa cell that operates at a primary frequency and means a cell in whichthe UE performs an initial connection establishment procedure or aconnection reestablishment procedure with the base station or a cellindicated by the primary cell during a handover procedure. The secondarycell means a cell that operates at a secondary frequency and once an RRCconnection is established, the secondary cell is configured and is usedto provide an additional radio resource.

The carrier aggregation system may be divided into a continuous carrieraggregation system in which aggregated carriers are contiguous and anon-contiguous carrier aggregation system in which the aggregatedcarriers are separated from each other. Hereinafter, when the contiguousand non-contiguous carrier systems are just called the carrieraggregation system, it should be construed that the carrier aggregationsystem includes both a case in which the component carriers arecontiguous and a case in which the component carriers arenon-contiguous. The number of component carriers aggregated between thedownlink and the uplink may be differently set. A case in which thenumber of downlink CCs and the number of uplink CCs are the same as eachother is referred to as symmetric aggregation and a case in which thenumber of downlink CCs and the number of uplink CCs are different fromeach other is referred to as asymmetric aggregation.

When one or more component carriers are aggregated, the componentcarriers to be aggregated may just use a bandwidth in the existingsystem for backward compatibility with the existing system. For example,in a 3GPP LTE system, bandwidths of 1.4 MHz, 3 MHz, 5 MHz, 10 MHz, 15MHz, and 20 MHz are supported and in a 3GPP LTE-A system, a wideband of20 MHz or more may be configured by using only the bandwidths of the3GPP LTE system. Alternatively, the wideband may be configured by notusing the bandwidth of the existing system but defining a new bandwidth.

Meanwhile, in order to transmit/receive packet data through a specificsecondary cell in the carrier aggregation, the UE first needs tocomplete configuration for the specific secondary cell. Herein, theconfiguration means a state in which receiving system informationrequired for data transmission/reception for the corresponding cell iscompleted. For example, the configuration may include all processes thatreceive common physical layer parameters required for the datatransmission/reception, media access control (MAC) layer parameters, orparameters required for a specific operation in an RRC layer. When theconfiguration-completed cell receives only information indicating thatthe packet data may be transmitted, the configuration-completed cell mayimmediately transmit/receive the packet.

The configuration-completed cell may be present in an activation ordeactivation state. Herein, the activation transmitting or receiving thedata or a ready state for transmitting or receiving the data. The UE maymonitor or receive the control channel (PDCCH) and the data channel(PDSCH) of the activated cell in order to verify resources (a frequency,a time, and the like) assigned thereto.

The deactivation represents that transmitting or receiving traffic datais impossible or measurement or transmitting/receiving minimuminformation is possible. The UE may receive system information SIrequired for receiving the packet from the deactivated cell. On thecontrary, the UE does not monitor or receive the control channel (PDCCH)and the data channel (PDSCH) of the deactivated cell in order to verifythe resources (the frequency, the time, and the like) assigned thereto.

<Transmission of Uplink Control Information (UCI)>

Uplink control information (UCI) may be transmitted on the PUCCH. Inthis case, the PUCCH carries various types of control informationaccording to a format. The UCI includes HARQ ACK/NACK, searching request(SR), and channel state information (CSI) indicating a downlink channelstate.

Hereinafter, periodic transmission and aperiodic transmission of the CSIwill be described.

The CSI as an index indicating a state of a DL channel may include atleast any one of a channel quality indicator (CQI) and a precodingmatrix indicator (PMI). Further, the CSI may include a precoding typeindicator (PTI), a rank indication (RI), and the like.

The CQI provides information on a link adaptive parameter which the UEmay support with respective to a given time. The CQI may be generated byvarious methods. For example, the various methods includes a method thatjust quantizes and feeds back the channel state, a method thatcalculates and feeds back a signal to interference plus noise ratio(SINR), a method that announces a state actually applied to the channel,such as a modulation coding scheme (MCS), and the like. When the CQI isgenerated based on the MCS, the MCS includes a modulation scheme, acoding scheme and the resulting coding rate. In this case, the basestation may determine m-phase shift keying (m-PSK) or m-quadratureamplitude modulation (m-QAM) and coding rate by using the CQI. A tablegiven below shows a modulation scheme, code rate, and efficiencydepending on a CQI index. The CQI index shown in the table given belowmay be expressed as 4 bits.

TABLE 1 CQI index Modulation Code rate × 1024 Efficiency 0 out of range1 QPSK 78 0.1523 2 QPSK 120 0.2344 3 QPSK 193 0.3770 4 QPSK 308 0.6016 5QPSK 449 0.8770 6 QPSK 602 1.1758 7 16QAM 378 1.4766 8 16QAM 490 1.91419 16QAM 616 2.4063 10 64QAM 466 2.7305 11 64QAM 567 3.3223 12 64QAM 6663.9023 13 64QAM 772 4.5234 14 64QAM 873 5.1152 15 64QAM 948 5.5547

The PMI provides information on a precoding matrix in precoding acodebook base. The PMI is associated with multiple input multiple output(MIMO). In the MIMO, feed-back of the PMI is called closed loop MIMO.

The RI represents information on the number layers recommended by theUE. That is, the RI represents the number of independent streams used inspatial multiplexing. The RI is fed back only when the UE operates in anMIMO mode using the spatial multiplexing. The RI is continuouslyassociated with one or more CQI feed-backs. That is, the CQI which isfed back is calculated assuming a specific RI value. Since a rank of thechannel is generally changed more slowly than the CQI, the RI is fedback at the smaller number of times than the CQI. A transmission periodof the RI may be multiple of a transmission period of the CQI/PMI. TheRI is given with respect all system bands and frequency selective RIfeed-back is not supported.

FIG. 6a illustrates one example of periodic CSI reporting in 3GPP LTE.

As seen with reference to FIG. 6a , the CSI may be periodicallytransmitted through a PUCCH 621 according to a period determined on ahigher layer. That is, the periodic channel state information (CSI) maybe transmitted through the PUCCH.

The UE may be semistatically configured by a higher layer signal so asto periodically feed back differential CSIs (CQI, PMI, and RI) throughthe PUCCH. In this case, the UE transmits the corresponding CSIaccording to modes defined as shown in a table given below.

TABLE 2 PMI feed-back time No PMI Single PMI PUCCH CQI feed- WidebandCQI Mode 1-0 Mode 2-0 back type Selective subband Mode 2-0 Mode 2-1 CQI

A periodic CSI reporting mode in the PUCCH described below is supportedfor each transmission mode.

TABLE 3 Transmission mode PUCCH CSI reporting modes Transmission mode 1Modes 1-0, 2-0 Transmission mode 2 Modes 1-0, 2-0 Transmission mode 3Modes 1-0, 2-0 Transmission mode 4 Modes 1-1, 2-1 Transmission mode 5Modes 1-1, 2-1 Transmission mode 6 Modes 1-1, 2-1 Transmission mode 7Modes 1-0, 2-0 Transmission mode 8 Modes 1-1, 2-1 when PMI/RI reportingis configured for the UE; modes 1-0, 2-0 when the PMI/RI reporting isnot configured for the UE Transmission mode 9 Modes 1-1, 2-1 when thePMI/RI reporting is configured for the UE and the number of CSI-RS portsis larger than 1. modes 1-0, 2-0 when the PMI/RI reporting is notconfigured for the UE or when the number of CSI-RS ports is 1

Meanwhile, a collision of the CSI reports represents a case in which asubframe configured to transmit a first CSI and a subframe configured totransmit a second CSI are the same as each other. When the collision ofthe CSI reports occurs, the first CSI and the second CSI may besimultaneously transmitted or transmission of a CSI having a lowerpriority may be dropped (alternatively, abandoned) a CSI having a higherpriority may be transmitted according to priorities of the first CSI andthe second CSI.

In the case of the CSI report through the PUCCH, various report typesmay be present as follows according to a transmission combination of theCQI/PMI/RI and period and offset values which are distinguishedaccording to each report type (hereinafter, abbreviated as a type) aresupported.

Type 1: Supports the CQI feed-back for a subband selected by the UE.

Type 1a: Supports a subband CQI and a second PMI feed-ack.

Types 2, 2b, 2c: Supports wideband CQI and PMI feed-backs.

Type 2a: Supports the wideband PMI feed-back.

Type 3: Supports an RI feed-back.

Type 4: Transmits a wideband CQI.

Type 5: Supports the RI and wideband PMI feed-back.

Type 6: Supports RI and PTI feed-backs.

Hereinafter, the aperiodic transmission of the CSI will be described.

FIG. 6b illustrates one example of aperiodic CSI reporting in the 3GPPLTE.

A control signal to request the CSI to be transmitted, that is, anaperiodic CSI request signal may be included in a scheduling controlsignal for the PUSCH transmitted to a PDCCH 612, that is, a UL grant. Inthis case, the UE aperiodically reports the CSI through a PUSCH 532. Asdescribed above, the CSI transmission on the PUSCH is referred to as theaperiodic CSI reporting in that the CSI transmission on the PUSCH istriggered by a request by the base station. The CSI reporting may betriggered by the UL grant or a random access response grant.

In more detail, the wireless device receives the UL grant includingscheduling information for the PUSCH 632 to the PDCCH 612 in subframe n.The UL grant may be included in a CQI request field. A table given belowshows one example of the CQI request field of 2 bits. A value or a bitcount of the CQI request field is just an example.

TABLE 4 Value of CQI request field Contents 00 CSI reporting is nottriggered 01 CSI reporting for a serving cell is triggered 10 CSIreporting for a first set of the serving cell is triggered 11 CSIreporting for a second set of the serving cell is triggered

The base station may announce to the wireless device information on thefirst and second sets for which the CSI reporting is triggered inadvance.

When the CSI reporting is triggered, the wireless device transmits theCSI on a PUSCH 620 in subframe n+k. Herein, k=4 or this is just anexample.

The base station may designate a reporting mode (reporting mode) of theCSI for the wireless device.

A table given below illustrates one example of the CSI reporting mode inthe 3GPP LTE.

TABLE 5 PMI feed-back type No PMI Single PMI Multiple PMI Wideband CQIMode 1-2 Selective subband CQI Mode 2-0 Mode 2-2 Set subband CQI Mode3-0 Mode 3-1

(1) Mode 1-2

The precoding matrix is selected on the assumption that DL data istransmitted through only the corresponding subband with respect to eachsubband. The wireless device assumes the precoding matrix selected withrespect to a system band or a band (referred to as a band set S)designated by the higher layer signal and generates the CAI (referred toas the wideband CQI).

The wireless device transmits the CSI including the wideband CQI and thePMI of each subband. In this case, the size of each subband may varydepending on the size of the system band.

(2) Mode 2-0

The wireless device selects M subbands preferred with respect to thesystem band or the band (the band set S) designated by the higher layersignal. The wireless device generates the subband CQI on the assumptionthat data is transmitted in selected M subbands. The wireless deviceadditionally generates one wideband CQI with respect to the system bandor the band set S.

The wireless device transmits information on the selected M subbands,the subband CQI, and the wideband CQI.

(3) Mode 2-2

The wireless device selects M preferred subbands and a single precodingmatrix for M preferred subbands on the assumption of transmitting the DLdata through M preferred subbands.

The subband CQIs for M preferred subbands are defined for each codeword.The wireless device generates the wideband CQI with respect to thesystem band or the band set S.

The wireless device transmits the CSI including M preferred subbands,one subband CQI, PMIS for M preferred subbands, the wideband PMI, andthe wideband CQI.

(4) Mode 3-0

The wireless device transmits the CSI including the wideband CQI and thesubband CQI for the configured subband.

(5) Mode 3-1

The wireless device generates the single precoding matrix with respectto the system band or the band set S. The wireless device assumes thegenerated single precoding matrix and generates the subband CQI for eachcodeword. The wireless device may assume the single precoding matrix andgenerate the wideband CQI.

Hereinafter, simultaneous transmission of the PUCCH and the PUSCH willbe described.

In a 3GPP release 8 or release 9 system, when the UE uses an SC-FDMAscheme in uplink transmission, the UE may not be allowed tosimultaneously transmit the PUCCH and the PUSCH on one carrier in orderto maintain a single carrier characteristic.

However, in a 3GPP release 10 system, whether to simultaneously transmitthe PUCCH and the PUSCH may be indicated on a higher layer. That is,according to the indication of the higher layer, the UE maysimultaneously transmit the PUCCH and the PUSCH or transmit only any oneof the PUCCH and the PUSCH.

FIG. 6c illustrates one example of simultaneous transmission of PUCCHand PUSCH.

As seen with reference to FIG. 6c , the UE receives PDCCH 613 in thesubframe n.

In addition, the UE may simultaneously transmit PUCCH 623 and PUSCH 633in for example, a subframe n+4.

The simultaneous transmission of the PUCCH and the PUSCH is defined asfollows in the 3GPP release 10 system.

It is assumed that the UE is configured for a single serving cell andthe PUSCH and the PUCCH are configured not to be simultaneouslytransmitted. In this case, when the UE does not transmit the PUSCH, theUCI may be transmitted through PUCCH format 1/1a/1b/3. The UE transmitsthe PUSCH and when the PUSCH does not correspond to a random accessresponse grant, the UCI may be transmitted through the PUSCH.

Unlike this, it is assumed that the UE is configured for the singleserving cell and the PUSCH and the PUCCH are configured to besimultaneously transmitted. In this case, when the UCI is constitutedonly by HARQ-ACK and SR, the UCI may be transmitted through the PUCCHformat 1/1a/1b/3. However, when the UCI is constituted only by theperiodic CSI, the UCI may be transmitted on the PUCCH through PUCCHformat 2. Alternatively, when the UCI is constituted by the periodic CSIand the HARQ-ACK and the UE does not transmit the PUSCH, the UCI may betransmitted on the PUCCH through PUCCH format 2/2a/2b. Alternatively,when the UCI is constituted only by HARQ-ACK/NACK, the UCI isconstituted by the HARQ-ACK/NACK and the SR, the UCI is constituted bypositive SR and the periodic/aperiodic CSI, or when the UCI isconstituted only by the aperiodic CSI, the HARQ-ACK/NACK, the SR, andthe positive SR may be transmitted to the PUCCH and theperiodic/aperiodic CSI may be transmitted through the PUSCH.

Further, unlike this, it is assumed that the UE is configured for one ormore serving cells and the PUSCH and the PUCCH are configured not to besimultaneously transmitted. In this case, when the UE does not transmitthe PUSCH, the UCI may be transmitted onto the PUCCH according to thePUCCH format 1/1a/1b/3. However, when the UCI is constituted by theaperiodic CSI or when the UCI is constituted by the aperiodic CSI andthe HARQ-ACK, the UCI may be transmitted through the PUSCH of theserving cell. Alternatively, when the UCI is constituted by the periodicCSI and the HARQ-ACK/NACK and the UE does not transmit the PUSCH in thesubframe n of a primary cell, the UCI may be transmitted on the PUSCH.

Further, unlike this, it is assumed that the UE is configured for one ormore serving cells and the PUSCH and the PUCCH are configured to besimultaneously transmitted. In this case, when the UCI is constituted byat least one of the HARQ-ACK and the SR, the UCI may be transmitted onthe PUCCH through the PUCCH format 1/1a/1b/3. However, when the UCI isconstituted only by the periodic CSI, the UCI may be transmitted ontothe PUCCH by using the PUCCH format 2. Alternatively, when the UCI isconstituted by the periodic CSI and the HARQ-ACK/NACK and the UE doesnot transmit the PUSCH, the CSI may not be transmitted but dropped(alternatively, abandoned). Alternatively, when the UCI is transmittedto the HARQ-ACK/NACK and the periodic CSI and the UE transmits the PUSCHon the subframe of the primary cell, the HARQ-ACK/NACK may betransmitted on the PUCCH by using the PUCCH format 1a/1b/3 and theperiodic CSI may be transmitted on the PUSCH.

FIG. 7 illustrates the PUCCH and the PUSCH on an uplink subframe.

PUCCH formats will be described with reference to FIG. 7.

The PUCCH format 1 carries the scheduling request (SR). In this case, anon-off keying (OOK) mode may be applied. The PUCCH format 1a carriesacknowledgement/non-acknowledgement (ACK/NACK) modulated in a binaryphase shift keying (BPSK) mode with respect to one codeword. The PUCCHformat 1b carries ACK/NACK modulated in a quadrature phase shift keying(QPSK) mode with respect to two codewords. The PUCCH format 2 carries achannel quality indicator (CQI) modulated in the QPSK mode. The PUCCHformats 2a and 2b carry the CQI and the ACK/NACK.

A table given below carries the PUCCH formats.

TABLE 6 Total bit Modulation count per Format mode subframe DescriptionFormat 1 Undecided Undecided Scheduling request (SR) Format 1a BPSK 1ACK/NACK of 1-bit HARQ, scheduling request (SR) may be present or notpresent Format 1b QPSK 2 ACK/NACK of 2-bit HARQ, scheduling request (SR)may be present or not present Format 2 QPSK 20 In case of extended CP,CSI and 1-bit or 2-bit HARQ ACK/NACK Format 2a QPSK + BPSK 21 CSI and1-bit HARQ ACK/NACK Format 2b QPSK + BPSK 22 CSI and 2-bit HARQ ACK/NACKFormat 3 QPSK 48 Multiple ACKs/NACKs, CSI, and scheduling request (SR)may be present or not present

Each PUCCH format is transmitted while being mapped to a PUCCH region.For example, the PUCCH format 2/2a/2b is transmitted while being mappedto resource blocks (m=0 and 1) of band edges assigned to the UE. A mixedPUCCH RB may be transmitted while being mapped to a resource block(e.g., m=2) adjacent to the resource block to which the PUCCH format2/2a/2b is assigned in a central direction of the band. The PUCCH format1/1a/1b in which the SR and the ACK/NACK are transmitted may be disposedin a resource block in which m=4 or m=5. The number (N(2)RB) of resourceblocks which may be used in the PUCCH format 2/2a/2b in which the CQI istransmitted may be indicated to the UE through a broadcasted signal.

Meanwhile, the PUSCH is mapped to an uplink shared channel (UL-SCH)which is a transport channel. Uplink data transmitted onto the PUSCH maybe a transport block which is a data block for the UL-SCH during a TTI.The transport block may include user data. Alternatively, the uplinkdata may be multiplexed data. The multiplexed data may be obtained bymultiplexing the transport block and the channel state information forthe uplink shared channel (UL-SCH). For example, the channel stateinformation (CSI) multiplexed to data may include the CQI, the PMI, theRI, and the like. Alternatively, the uplink data may be constituted onlyby the channel state information. The periodic or aperiodic channelstate information may be transmitted through the PUSCH.

The PUSCH is assigned by the UL grant on the PDCCH. Although notillustrated in FIG. 7, a fourth OFDM symbol of each slot of a normal CPis used in transmission of a demodulation reference signal (DM RS) forthe PUSCH.

<Introduction of Small Cell>

Meanwhile, in a next-generation mobile communication system, it isanticipated that a small cell having a small cell coverage radius willbe added into coverage of the existing cell and it is anticipated thatthe small cell will process more traffic. Since the existing cell haslarger than the small cell, the existing call may be called a macrocell. Hereinafter, the macro cell will be described with reference toFIG. 10.

FIG. 8 is a diagram illustrating an environment of heterogeneousnetworks of a macro cell and a small cell which may become anext-generation wireless communication system.

Referring to FIG. 8, a heterogeneous-network environment is shown, inwhich a macro cell by the existing base station 200 overlaps with asmall cell by one or more small base stations 300 a, 300 b, 300 c, and300 d. Since the existing base station provides the larger coverage thanthe small base station, the existing base station may be called themacro base station (macro eNodeB, MeNB). In the present specification,terms such as the macro cell and the macro base station will be mixedand used. The UE that accesses the macro cell 200 may be called macroUE. The macro UE receives a downlink signal from the macro base stationand transmits an uplink signal to the macro base station.

In the heterogeneous networks, the macro cell is configured as a primarycell (Pcell) and the small cell is configured as a secondary cell(Scell) to fill a coverage gap of the macro cell. Further, the smallcell is configured as the primary cell (Pcell) and the macro cell isconfigured as the secondary cell (Scell) to boost overall performance.

Meanwhile, the small cell may use a frequency band assigned to currentLTE/LTE-A or use a higher frequency band (e.g., a band of 3.5 GHz orhigher).

On the other hand, in a next LTE-A system, it is considered that thesmall cell may not be independently used and the small cell may be usedonly as a macro-assisted small cell which may be used under assistanceof the macro cell.

The small cells 300 a, 300 b, 300 c, and 300 d may have similar channelenvironments to each other and since the small cells 300 a, 300 b, 300c, and 300 d are positioned at distances which are proximate to eachother, interference among the small cells may be large.

In order to reduce an interference influence, the small cells 300 b and300 c may extend or reduce coverage thereof. The extension and reductionof the coverage is referred to as cell breathing. For example, asillustrated in FIG. 8, the small cells 300 b and 300 c may be turned onor off according to a situation.

On the other hand, the small cell may use the frequency band assigned tothe current LTE/LTE-A or use the higher frequency band (e.g., a band of3.5 GHz or higher).

Meanwhile, the UE may be dually connected to the macro cell and thesmall cell. Scenarios in which the dual connectivity is possible areillustrated in FIGS. 9a and 9 b.

FIGS. 9a and 9b illustrate scenarios of dual connectivity possible withrespect to the macro cell and the small cell.

As illustrated in FIG. 9a , the UE may configure the macro cell as acontrol-plane (hereinafter, referred to as ‘C-plane’) and configured thesmall cell as a user-plane (hereinafter, referred to as ‘U-plane’).

Alternatively, as illustrated in FIG. 9b , the UE may configure thesmall cell as the C-plane and configure the macro cell as the U-plane.In the present specification, for easy description, a cell of theC-plane will be called ‘C-cell’ and a cell of the U-plane will be called‘U-cell’.

Herein, the mentioned C-plane means supporting a procedure required forRRC connection configuration and reconfiguration, an RRC idle mode,mobility including handover, cell selection and reselection, an HARQprocess, configuration and reconfiguration of carrier aggregation (CA),and RRC configuration, a random access procedure, and the like. Inaddition, the mentioned U-plane means supporting data processing of anapplication, CSI reporting, an HARQ process for application data, amulticasting/broadcasting, and the like.

From the viewpoint of the UE, the C-plane and the U-plane are configuredas follows. The C-cell may be configured as the primary cell and theU-cell may be configured as the secondary cell. Alternatively, contraryto this, the U-cell may be configured as the primary cell and the C-cellmay be configured as the secondary cell. Alternatively, the C-cell maybe separately particularly processed and the U-cell may be configured asthe primary cell. Alternatively, both the C-plane and the U-cell may beconfigured as the primary cell. However, in the present specification,for easy description, the configuration of the cell will be described onthe assumption that the C-cell is configured as the primary cell and theU-cell is configured as the secondary cell.

Meanwhile, since the handover may excessively frequently occur under asituation in which the UE 100 frequently moves within a short distance,it may be advantageous that the UE may configure the macro cell as theC-cell or the primary cell and the small cell may configure the smallcell as the U-cell or the secondary cell in order to prevent thehandover which excessively frequently occurs.

Due to such a reason, the macro cell as the primary cell of the UE maybe continuously connected with the UE.

Meanwhile, in FIGS. 9a and 9b , it is illustrated that the UE is duallyconnected with the eNodeB of the macro cell and the eNodeB of the smallcell, but the present invention is not limited thereto. For example, theUE may be dually connected to first eNodeB for a first small cell(alternatively, a group of the first small cells) and second eNodeB fora second small cell (alternatively, a group of the second small cells).

When all examples given above are considered, eNodeB for the primarycell (Pcell) may be referred to as master eNodeB (hereinafter, referredto as MeNB). In addition, eNodeB for only the secondary cell (Scell) maybe referred to as secondary eNodeB (hereinafter, referred to as SeNB).

A cell group including the primary cell (Pcell) by the MeNB may bereferred to as a master cell group (MCG) and a cell group including thesecondary cell (Scell) by the SeNB may be referred to as a secondarycell group (SCG).

Meanwhile, as described above, in a next system, a situation may beconsidered, in which the UE transmits/receives a control signal/controldata to/from a plurality of cells or cell groups in which geographicallocations are different from each other. For example, a type may beconsidered, in which the UE is simultaneously connected to the MCGincluding the primary cell which processes RRC connection and a voiceand the SCG including the small cells for increasing data processing. Inthis case, the scheduling information may not be dynamically sharedamong the plurality of cells or cell groups in which the geographicallocations are different from each other and scheduling may beindependently performed. In this case, it may be considered that the UEindependently transmits the UCI to each corresponding cell. In otherwords, it may be considered that the UE transmits the UCI for the MCG tothe MeNB and transmits the UCI for the SCG to the SeNB.

However, when the subframe in which the PUCCH/PUSCH including the UCIfor the MeNB is transmitted and the subframe in which the PUCCH/PUSCHincluding the UCI for the SeNB is transmitted partially overlap witheach other, a problem may occur.

In respect to a similar problem situation, in the existing system, finaltransmission power of all or some uplink channels is scaled downaccording to maximum transmission power of the UE. A criterion fordetermining channels to be reduced follows a priority rule in which atype of the channel, a cell index, and the like are considered. As oneexample, under a situation in which the PUCCH and the PUSCH aresimultaneously transmitted to a predetermined cell on any one subframe,according to the existing system, power assignment and scale-down areperformed in the order of the PUCCH, the PUSCH including the UCI, andthe residual PUSCH according to Pcmax. Further, according to theexisting system, some uplink channels may be dropped according tosimultaneous transmission performance of the UE or simultaneoustransmission related parameter configuration from the higher layer andin this case, the corresponding channel is selected according to thepriority rule. As one example, when the HARQ-ACK and the CSI areconfigured to be simultaneously transmitted, in the case where theHARQ-ACK and the CSI collide with each other in the same subframe, theCSI is dropped.

However, as described above, in the next system, the UCI may beseparately transmitted for each cell group and the priority rule needsto be changed while the RRC connection configuration of only some cellgroups is managed. Hereinafter, disclosures of the present specificationwill be described.

<First Disclosure of Present Specification>

The first disclosure of the present specification presents a method thatconfigures and applies a plurality of priority rules (alternatively,modes).

Under the dual-connectivity situation, the primary cell (Pcell) (e.g.,the macro cell) takes charge of the RRC connection configuration andreconfiguration and takes charge of a voice call in that the primarycell is differentiated from the secondary cell. A meaning that theprimary cell takes charge of the RRC connection configuration andreconfiguration may be construed as a meaning that (E)PDCCH, PDSCH, andPUSCH which may be transmitted during a process of configuring orchanging the RRC connection are transmitted only through thecorresponding primary cell (Pcell) (e.g., the macro cell). Further, ameaning that the primary cell takes charge of the voice call may beconstrued as a meaning that a combination of DL SPS PDSCH and UL SPSPUSCH are transmitted only through the primary cell (e.g., the macrocell) for the purpose of supporting voice over LTE (VoLTE). In thiscase, a case in which the UCI including the HARQ-ACK, the CSI, the SR,and the like corresponds to the primary cell (Pcell) (e.g., the macrocell) may be considered to be more important than a case in which theUCI corresponds to the secondary cell (Scell) (e.g., the small cell) andthis may be considered even when the priority rule for the dualconnectivity is configured. However, even when the secondary cell (e.g.,the small cell) is operated for the purpose of boosting the dataprocessing, restriction (e.g., dropping or power scale-down) of the UCI(the HARQ-ACK, the CSI, and the like) may degrade performance ordecrease efficiency. As a result, it may be considered that the priorityrule is configured and applied independently (to be different) for eachsubframe or for each section of the subframe. By a more detailed method,the cell may configure a first priority rule (alternatively, a firstmode) and second priority rule (alternatively, a second mode) andconfigure the subframe or the subframe section to which each priorityrule (alternatively, mode) will be applied for the UE through the higherlayer signal. When the UE does not obtain the configuration for thepriority rule (alternatively, the mode) which will be applied to thesubframe or the subframe section, the UE may apply one priority rule(alternatively, mode). This will be described in more detail withreference to the drawings.

FIG. 10 is an exemplary diagram illustrating one method according to afirst disclosure of the present specification.

As seen with reference to FIG. 10, UE 100 has dual connectivity with afirst cell and a second cell. In such a situation, the UE 100 receives ahigher layer signal from the first cell. The higher layer signalincludes any one of a first configuration and a second configuration.Herein, the first configuration may mean a first priority rule(alternatively, a first mode) and the second configuration may representa second priority rule (alternatively, a second mode).

Then, the UE 100 performs power adjustment based on the firstconfiguration or the second configuration and performs uplinktransmission based on the power.

As one example of utilization, in a section in which the second priorityrule (alternatively, the second mode) of configuring a priority of theprimary cell (Pcell) (e.g., the macro cell) high, the RRC configurationor the voice call is performed, and as a result, performance of thecorresponding operation may be maximized and in a section in which thefirst priority rule (alternatively, the first mode) of configuring thepriority of the secondary cell (Scell) (e.g., the small cell) high, datacommunication such as FTP, or the like is performed, and as a result,boosting data processing increase may be performed. A basic operation ofthe UE may follow the second priority rule (alternatively, the secondmode) of configuring the priority of the primary cell (Pcell) (e.g., themacro cell) high so as to focus on an initial RRC configuration.

Hereinafter, detailed methods will be described.

1. Configuration and Application Method of First Priority Rule(Alternatively, First Mode)

Fundamentally, the high priority may not be unconditionally configuredwith respect to the primary cell (PCell) (e.g., the macro cell) or thecell group (e.g., the MCG) including the primary cell, but the prioritymay be configured based on other factors (e.g., a UCI type, a powerlevel, a type of the channel, a UCI size, a frame structure type, a CPlength, and the like). Under a situation in which the priorities are thesame as each other, it may be considered that the priority is configuredaccording to information on the cell, e.g., a cell index, a type (e.g.,eNodeB of the macro cell or eNodeB of the small cell) of eNodeB of thecorresponding cell, whether the corresponding cell corresponds to a cellin which PUCCH transmission is available, and the like.

As one example, the priority may be configured according to the UCI typeregardless of the transport channel (PUCCH or PUSCH). By a more detailedmethod, the HARQ-ACK, the SR, the aperiodic CSI, the aperiodic SRS, theperiodic CSI, and the periodic SRS may be configured to have higherpriorities in the order thereof. In this case, when the UCI isconfigured by a plurality of combinations, power scaling and abandonmentare determined based on a combination having a highest priority. As oneexample, under a situation in which the HARQ-ACK and the periodic CSIare simultaneously transmitted, the power scaling and the abandonmentmay be determined based on the HARQ-ACK having the highest priority. Inmore distinctive, when the HARQ-ACK corresponds to a common search space(CSS), the HARQ-ACK may be configured to have a higher priority thanother HARQ-ACK or PRACH. The HARQ-ACK corresponding to the CSS may belimited with respect to the primary cell (PCell).

In the enumerated priority rules, the priority of the SPS PUSCH may bedistinctively configured to be high and a detailed example thereof willbe described below.

As a first example, the priority may be configured in the order ofPUCCH/PUSCH<SPS PUSCH<=HARQ-ACK including the CSI and/or PUCCH/PUSCHincluding the SR.

A second example is PUCCH/PUSCH including SPS PUSCH=CSI.

A third example is PUSCH including SPS PUSCH=aperiodic CSI.

The SPS PUSCH may be a case in which the SPS PUSCH may be used for avoice communication purpose (including even a partial case in which theSPS PUSCH is not actually used) or a case in which the SPS is configuredonly for a specific cell.

Thereafter, a detailed priority may be configured based on theinformation on the cell according to the same priority and a detailedexample of the priority rule depending on the information on the cellwill be described below. In the example given below, a super secondarycell (Super SCell) may indicate the secondary cell (SCell) transmittingthe UCI or receiving the PUCCH among the secondary cells in thesecondary cell group (SCG). The super secondary cell (super SCell) maybe referred to as PSCell. This may correspond to small eNodeB. Inaddition, the secondary cell group (SCG) means a set of cells which arecarrier-aggregated (CA) in the super secondary cell (e.g., the smalleNodeB) and the primary cell group (PCell group) means the primary celland a set of cells which are carrier-aggregated (CA) in the eNodeBproviding the primary cell. The primary cell group (PCell group) may bereferred to as the master cell group (MCG). Ideal backhaul may beassumed among the cells carrier-aggregated by the same eNodeB and theideal backhaul may not be anticipated among cells corresponding todifferent eNodeBs.

As a first exemplary priority, the primary cell (PCell)>the supersecondary cell (alternatively, PSCell)>the secondary cell (e.g., thesecondary cell of the small eNodeB) corresponding to the secondary cellgroup (SCG)>=the secondary cells (e.g., the secondary cells of MacroeNodeB) corresponding to the primary cell group (alternatively, theMCG).

As a second exemplary priority, the primary cell (PCell)>the supersecondary cell (alternatively, PSCell)>the secondary cells (e.g., thesecondary cell of the macro eNodeB) corresponding to the primary cellgroup (alternatively, MCG)>=the secondary cells (e.g., the secondarycells of the small eNodeB) corresponding to the SCG.

As a third exemplary priority, the primary cell (PCell)>the secondarycells corresponding to the primary cell group (alternatively, MCG)>thesuper secondary cell (alternatively, PSCell)>=the secondary cells (e.g.,the secondary cells of the small eNodeB) corresponding to the SCG.

In configuring a first priority rule (alternatively, a first mode), anexception for a specific situation or condition may be additionallyconsidered in order to configure the priorities of some physicalchannels of the MCB (alternatively, MeNB or PCell) to be high. Referringto the first priority rule (alternatively, the first mode), thepriorities of all or some channels of the MCG may be configured to behigher than the SCG in the following situation. As one example, althoughthe PUCCH including the HARQ-ACK is transmitted through the SCG and thePUSCH not including the UCI is transmitted through the MCG, the priorityof the PUSCH for the MCG may be configured to be higher than thepriority of the HARQ-ACK PUCCH for SCG under exemplary situationsenumerated below.

A first exemplary situation may include a situation in which the PDCCHincluding the UL grant for the channel (e.g., the PUSCH) correspondingto the MCG is transmitted. Herein, the case in which the PDCCH istransmitted in the CSS may mean that the PDCCH scrambled with a commonC-RNTI is transmitted or mean that a physical resource mapping locationof the PDCCH is the CSS. A case in which the channel corresponding tothe MCG is the PUCCH (in particular, the HARQ-ACK) may include even acase in which the PDCCH corresponding to the UCI of the correspondingPUCCH corresponds to the CSS.

A first exemplary situation may include a situation in which the poweris set to a minimum power value or more, which is set previously or onthe higher layer at the time of performing the power scaling for thechannel (e.g., the PUSCH) corresponding to the MCG. In this case, thePUCCH for the SCG may be dropped or power-scaled and the priority of thePUSCH for the MCG may be configured to be higher than the priority ofthe PUCCH for the SCG.

A third exemplary situation may include a situation in which thepriority is reconfigured according to a transmission mode of the uplinkgrant for the channel (e.g., the PUSCH) corresponding to the MCG.Herein, the transmission mode of the uplink grant may be dividedaccording to a scrambling sequence, CRC masking or a specific value fora new field or a specific combination of some existing field values.

As a fourth exemplary situation, in the case where minimum power for thechannel (e.g., the PUCCH) corresponding to the SCG is predetermined ordetermined according to the higher layer signal, when the power of thechannel for the corresponding SCG is equal to or less than or less thanthe minimum power value, the priority of the channel for the MCG isconfigured to be high.

2. Configuration and Application Method of Second Priority Rule(Alternatively, Second Mode)

Fundamentally, the priority for the primary cell (PCell) or the primarycell group (that is, the MCG) is configured to be the highest. However,the SRS for the primary cell (PCell) or the primary cell group (that is,the MCG) may be excluded. In this case, in the UE, when transmission ofan uplink channel for a plurality of cells requires power of Pcmax, thepower scaling (e.g., down-scaling) may not be performed with respect tothe channel for the primary cell (PCell) or the primary cell group (thatis, the MCG). The following channels may not correspond to the abovechannels. The PUSCH which does not include the SRS and the UCI and doesnot correspond to a grant in the random access response (PAR) orretransmission for the random access procedure. The reason is to protectRRC configuration and reconfiguration or primary communication such asthe voice communication. Alternatively, when the priority for theprimary cell (PCell) or the primary cell group (that is, the MCG) isconfigured to be the highest, the channel which is not power-scaled maybe the PRACH/PUCCH/SPS PUSCH. In other words, only when the PRACH,PUCCH, or SPS PUSCH is transmitted to the primary cell (PCell) or theprimary cell group (that is, the MCG), the priority may be given to thecorresponding channel the first priority rule (alternatively, the firstmode) may be applied to the residual channels. In this case, when thepriority is given, a case in which the power-scaling is not performedmay be assumed. Thereafter, the operation according to the firstpriority rule (alternatively, the first mode) may be considered withrespect to the residual cell. In the above description, when the cellhaving the highest priority is limited to the primary cell in theprimary cell group (that is, the MCG), the first priority rule(alternatively, the first mode) may be applied to the residual channels.Additionally, in a similar method, a third priority of configuring thepriority (continuously or with respect to a specific UCI or channel) forthe super secondary cell (SCell) or PSCell instead of the primary cell(PCell) or the primary cell group (that is, the MCG) may be considered.

In more detail, the power scaling among the cell groups or thetransmission dropping of the channel may be determined based on thefollowing priority set at the time of determining the power scalingamong the cell groups or the transmission dropping of the channel. Inthis case, whether the power scaling is performed and whether thepriority for MeNB is configured to be high may be determined for eachset.

Set 0: PRACH

Set 1: SR, HARQ-ACK

Set 2: aperiodic CSI, periodic CSI

Set 3: SPS PUSCH

Set 4: PUSCH without UCI (UL-SCH)

Set 5: SRS

Set 6: D2D channels

According to the indexes of the sets, it may be assumed that the lowerthe index is, the higher, the priority is. Alternatively, it may beconsidered that set 0 and set 1 have the same priority, set 2 and set 3have the same priority, set 1 and set 2 have the same priority, or set1, set 2, and set 3 have the same priority. In the case of the set 1, inmore detail, it may be considered that the SR has the higher prioritythan the HARQ-ACK. The SR may be limited to the positive SR. As oneexample, when the UE transmits only the HARQ-RACK to the MCG by usingPUCCH format 3 and transmits the HARQ-ACK and the SR to the SCG throughthe PUCCH format, it may be considered that the higher priority is givento the SCG in the case of the positive SR and the high priority is givento the MCG in the case of the MCG. When the SR is transmitted throughthe PUCCH format 1/1a/1b, since the PUCCH is not transmitted or thePUCCH is transmitted through the HARQ-ACK resource in the case of theSR, it may be construed that the SR is not transmitted. In the abovedescription, the power scaling may not be performed with respect to acombination {set 0, set 1}, {set 0, set 1, set 2}, or {set 0, set 1, set2, set 3}. In this case, when power to be allocated is short, it may beconsidered that the UE drops transmission of the corresponding channel.When the power remains by dropping the transmission of the correspondingchannel, it may be considered that the remaining power is allocated to achannel having the second highest priority and it may be considered thatthe remaining power is not used. Fundamentally, when different cellgroups (MCG and SCG) correspond to the same set or when the differentcell groups correspond to the same priority set, the high priority maybe given to the MCG or the primary cell (PCell). In the abovedescription, it may be considered that the priority configuration isapplied with respect to a combination {set 2, set 3, set 4, set 5}, {set2, set 3, set 4}, {set 4, set 5}, or {set 4} equally or by giving aweight for each set without distinguishment at the time of the powerscaling for a simple operation. Herein, it may be limited that theweight is predetermined or set on the higher layer according to the setsor a group of the priority sets. When the channel corresponding to theset 5 collides with the residual channels other than the set 5, it maybe considered that transmission of the channel corresponding to the set5 is dropped. In a subsequent process, the power scaling may beperformed or the transmission of the corresponding channel may bedropped according to an

Rel-11 principle.

For example, when it is assumed that the set 1 and the set 2 have thesame priority, the following priority rule may be considered.

-   -   The PRACH to be transmitted to the MeNB has the highest priority    -   The PRACH has the highest priority than other channels        regardless of destination eNB    -   The PUSCH including the PUCCH or UCI to be transmitted to the        MeNB has the higher priority than the PUSCH including the PUCCH        or the UCI to be transmitted to the MeNB    -   The PUSCH including the PUCCH or UCI has the higher priority        than the PUSCH not including the UCI or SRS

The power scaling may not be performed with respect to the PUSCHincluding the PUCCH or the UCI. The same power scaling (alternatively,power scaling to which the weight is applied) may be performed withother channels.

A table given below is a table in which priority configuration isorganized when heterogeneous eNBs collide with each other.

TABLE 7 MeNB Set 0 Set 1 Set 2 Set 3 Set 4 Set 5 SeNB Set 0 MeNB OptionOption Option Option SeNB 1: MeNB 1: MeNB 1: MeNB 1: MeNB Option OptionOption Option 2: SeNB 2: SeNB 2: SeNB 2: SeNB Set 1 MeNB Option OptionOption Option SeNB 1: MeNB 1: MeNB 1: MeNB 1: MeNB Option Option OptionOption 2: SeNB 2: SeNB 2: SeNB 2: SeNB Set 2 MeNB Option Option OptionOption SeNB 1: MeNB 1: MeNB 1: MeNB 1: MeNB Option Option Option Option2: SeNB 2: SeNB 2: SeNB 2: SeNB Set 3 MeNB Option Option Option OptionSeNB 1: MeNB 1: MeNB 1: MeNB 1: MeNB Option Option Option Option 2: SeNB2: SeNB 2: SeNB 2: SeNB Set 4 MeNB Option Option Option Option SeNB 1:MeNB 1: MeNB 1: MeNB 1: MeNB Option Option Option Option 2: SeNB 2: SeNB2: SeNB 2: SeNB Set 5 MeNB MeNB MeNB MeNB MeNB Option 1: Equal Option 2:MeNB

Among the detailed options shown above, an option to configuring thepriority for the MeNB high, that is, option 1 may be fundamentallyconsidered. However, set 4 of the MeNB may have a lower priority thanset 0, set 1, set 2, and set 3 of the SeNB. Alternatively, when thechannel to be transmitted to the MeNB and the channel to be transmittedto the SeNB correspond to the same set, the channel to be transmitted tothe MeNB may have the higher priority. Alternatively, when the channelsto be transmitted to the MeNB correspond to a plurality of sets, thechannels to be transmitted to the MeNB may have the higher priority.Matters are enumerated below, which may be considered together with thecriterion.

-   -   In the case of set 1, the higher priority may be given to only        the SR to be transmitted to the SeNB according to the higher        layer signal. When the channel to be transmitted to the MeNB        corresponds to set 1 and similarly, the channel to be        transmitted to the SeNB also corresponds to set 1, the SR may        not be transmitted among the channels to be transmitted to the        MeNB. In this case, the SR which is not transmitted may be the        negative SR. The higher layer signal may be referred to as the        priority of the SeNB for the SR and may be a parameter        associated with bearer split in an MAC layer. As one example,        when the bearer is assigned only to the SeNB, the SR for the        SeNB may be configured to be higher than the HARQ-ACK of the        MeNB. In this case, the SR may the positive SR.    -   When the channel to be transmitted to the MeNB corresponds to        SET 5 and similarly, the channel to be transmitted to the SeNB        also corresponds to set 5, the same priority may be used.

A table given below is a table in which when a plurality of channels istransmitted for each eNB, the priority configuration between the eNBs isorganized.

TABLE 8 MeNB PUCCH/PUSCH/ PRACH PUCCH PUSCH PUCCH/PUSCH SRS SeNB PRACHTable 7 Table 7 Table 7 Transmission drop of the SRS ==> According toTable 7. Further, power scaling of the PUSCH PUCCH Table 7 Table 7 Table7 According to Transmission drop Table 7. of the SRS ==> Further,According to power scaling Table 7. Further, of the PUSCH power scalingof the PUSCH PUSCH Table 7 Table 7 Table 7 According to Transmissiondrop Table 7. of the SRS ==> Further, According to power scaling Table7. Further, of the PUSCH power scaling of the PUSCH PUCCH/ PRACH >According According According to Transmission drop PUSCH PUCCH to toTable 7. of the SRS ==> Further, Table 7. Table 7. Further, According topower Further, Further, power scaling Table 7. Further, scaling powerpower of the PUSCH power scaling of of the scaling scaling the PUSCHPUSCH of the of the PUSCH PUSCH PUCCH/ Transmission TransmissionTransmission Transmission Transmission drop PUSCH/ drop drop of drop ofdrop of the of the SRS ==> SRS of the the the SRS ==> According to SRS==> SRS ==> SRS ==> According to Table 7. Further, PRACH > AccordingAccording Table 7. power scaling of PUCCH to to Further, the PUSCHFurther, Table 7. Table 7. power scaling power Further, Further, of thePUSCH scaling power power of the scaling scaling PUSCH of the of thePUSCH PUSCH

The following description is a detailed example for a method forconfiguring the priorities among the channels to be transmitted to thePCell or the primary cell group (that is, MCG). The following priorityrule may be considered at the time of configuring the power of thechannels to be transmitted to the PCell or at the time of applying arule for dropping the channel to be transmitted to the PCell.

2.1 PUSCH PUCCH

Using the UL SPS PUSCH may be considered for the purpose of supportingthe voice communication and in this case, it may be considered that thepriority of the corresponding PUSCH is configured to be high. Next, oneexample of configuring the priorities for the PUCCH and the UL SPS PUSCHwill be described.

As a first option, a priority order is determined according to the UCIincluded in the PUCCH. As a more detailed example, the priorities areconfigured in the following order.

As a first example of the first option, PUCCH including the periodicCSI<the UL SPS PUSCH<=the PUCCH including the HARQ-ACK/SR

As a second example of the first option, the PUCCH including theperiodic CSI<PUCCH including the HARQ-ACK/SR<the UL SPS PUSCH

As a third example of the first option, the UL SPS PUSCH<the PUCCHincluding the periodic CSI<the PUCCH including the HARQ-ACK/SR

In the above examples, only the PUCCH including the positive SR does notinclude the SR and may have the higher priority than the PUCCH includingthe HARQ-ACK.

As a second option, the priority for the primary cell (PCell) in theprimary cell group (that is, the MCG) is configured to be the highest.The second option may be used for a case in which the priority for theprimary cell group (that is, the MCG) is configured to be high and thenumber of cells in the primary cell group (that is, the MCG) ismultiple.

Herein, when the PUCCH includes the HARQ-ACK/SR, it is not excluded thatthe PUCCH includes even the periodic CSI, but when the PUCCH includesthe periodic CSI, the PUCCH may include only the periodic CSI. It may beconsidered that the priority rule of the existing 3GPP Rel-12 isfollowed with respect to the PUSCH other than the UL SPS PUSCH of thecorresponding cell.

2.2 PUSCH and PUSCH

Contents described below relate to the case in which the priority of theprimary cell group (that is, the MCG) is configured to be high. TheMacro eNodeB may aggregate the plurality of cells and in this case, thepriority rule according to the existing 3GPP Rel-12 may be just appliedand the priority for the SPS PUSCH may be reconfigured for the purposeof protecting the voice communication. Next, one example of configuringthe priorities for the UL

SPS PUSCH and the PUSCHs of other cells of the primary cell group (thatis, the MCG) will be described.

As a first method, the priority order is determined according to thepresence or the type of the UCI included in the PUSCH. As a moredetailed example, the priorities are configured in the following order.

As a first option of the first method, the PUSCH including the periodicCSI<the UL SPS PUSCH<the PUSCH including the aperiodic PUSCH

As a second option of the first method, the PUSCH including theperiodic/aperiodic CSI<the UL SPS PUSCH<=the PUSCH including theHARQ-ACK

As a third option of the first method, the PUSCH including theHARQ-ACK<the UL SPS PUSCH

As a second method, the priority order is determined based on the UL-SCHincluded in the PUSCH and the number of assigned RBs. As a more detailedexample, when coding rate of the PUSCH is lower than coding rate of theUL SPS PUSCH by a predetermined threshold or more, the priority of theUL SPS PUSCH is configured to be high.

As a third method, the priority of the channel for the PCell in theprimary cell group (that is, the MCG) is configured to be the highest.In this option, the priority for the primary cell group (that is, theMCG) is configured to be high and this option may be limited to the casewhere the number of cells in the primary cell group (that is, the MCG)is multiple.

<Second Disclosure of Present Specification>

The second disclosure of the present specification presents a methodthat guarantees minimum power for each eNodeB, for each cell group, orfor each cell.

In a next system, configuring power which the UE may minimally guaranteemay be introduced in order for the UE to guarantee transmission to eacheNodeB (alternatively, each cell group or a specific cell in each cellgroup) while dual connectivity. As one example, when the UE isconfigured with transmission power to a second eNodeB as Pcmin2, eventhough a priority of a first eNodeB is configured to be high, it may beconsidered that the transmission power to the second eNodeB isconfigured as at least Pcmin2 or more. Each eNodeB/cell group/cell maydetermine and announce power or a power value for each channel which theUE may minimally guarantee.

In this case, the power or the power value for each channel is includedin a consideration target in power control (e.g., power scaling ortransmission dropping) for the UL channels transmitted to the firsteNodeB and the second eNodeB according to the configured UE minimumpower.

1. Case where Minimum Transmission Power (Minimum UE Transmission Power)for First eNodeB (e.g., MeNB) is Configured

In dual connectivity, the MeNB takes charge of RRC connectionconfiguration, mobility handling, and the like, and as a result, ingeneral, the priority of an uplink channel for the MeNB may beconfigured to be higher than the priority of the uplink channel for theSeNB. Further, the uplink channel may correspond to for example, PRACH,PUCCH, SPS, PUSCH, and PUSCH including UCI. This may be used forreserving the minimum UE transmission power for the MeNB in order toguarantee transmission performance of all or some of the uplink channelsto the MeNB. Herein, when a value of power actually scheduled by theMeNB is smaller than the minimum UE transmission power, the scheduledpower value may be used instead of the minimum UE transmission power.

When final transmission power (a total sum of power for each channel) ofat least one of the MCG and the SCG is smaller than the minimum UEtransmission power P_xeNB initially configured for each eNodeB, it ismay be considered that residual power (e.g., P_CMAX−P_MeNB orP_CMAX−P_SeNB) is assigned to other cell groups. In this case, othercell groups may assign the minimum transmission power with the residualpower (P_CMAX-total allocated power to the other eNodeB) as the upperlimit. In this case, after the UE configures the assigned power withmaximum power which may be used thereby, the UE may assign the power toeach channel by applying the rule according to the existing Rel-11. Inthis case, in a situation in which timings do not synchronize with eachother, for example, a situation in which two subframes overlap with eachother, a value of power which is not used throughout two subframes needsto become a minimum value. That is, min{P_CMAX(I,k)−P_alloc_xeNB(k),P_CMAX(I, k+1)−P_alloc_xeNB(k+1)} may be used. The UE may operate apower scaling method in a power limit situation (when total UE power ismore than Pcmax) by the following mode. In the embodiment, the firsteNodeB will be described as the MeNB and the eNodeB2 will be describedas the SeNB for easy description.

As a first example, UE transmission power for transmitting the PUSCH isconfigured as the minimum power. In this case, the transmission of thePUSCH may correspond to retransmission. Further, herein, the PUSCH maynot include a PUSCH corresponding to the SPS PUSCH or the random accessprocedure. As one example, the PUSCH corresponding to the random accessprocedure may be configured as the minimum power or more even in thepower limit.

As a second example, when the uplink channel (the uplink channel on allsubframes or some subframes by considering an overlapped part in thesituation in which the timings do not synchronize with each other)transmitted to the SeNB corresponds to {Set 0, Set 1, Set 2, Set 3},{Set 0, Set 1, Set 2}, or {Set 0, Set 1}, the UE transmission power forthe PUSCH to be transmitted to the MeNB is configured as the minimumpower. In this case, the PUSCH for the MeNB may be retransmitted.

2. Case where Minimum UE Transmission Power for Second eNodeB (e.g.,SeNB) is Configured

When the priorities for all or some uplink channels to be transmitted tothe MeNB are configured to be high in the dual connectivity, the poweris scaled so that the uplink channel (e.g., including the PUCCH to thePSCell) for the SeNB is transmitted with excessively low power, and as aresult, spectral efficiency may deteriorate. As a countermeasuretherefor, it may be considered that the minimum UE transmission power isconfigured with respect to all or some uplink channels for the SeNB andthe minimum UE transmission power is guaranteed. For example, when thetotal power value actually scheduled by the second eNodeB is smallerthan the minimum UE transmission power configured with respect to thesecond eNodeB, the corresponding value may be substituted with theminimum UE transmission power value. When final transmission power (atotal sum of power for each channel) of at least one of the MCG and theSCG is smaller than the minimum UE transmission power P_xeNB initiallyconfigured for each eNodeB, it is may be considered that residual power(e.g., P_CMAX−P_MeNB or P_CMAX−P_SeNB) is assigned to other cell groups.In this case, other corresponding cell groups may assign the minimumtransmission power with the residual power (P_CMAX-total allocated powerto the other eNodeB) as the upper limit. In this case, in a situation inwhich timings do not synchronize with each other, for example, asituation in which two subframes overlap with each other, a value ofpower which is not used throughout two subframes needs to become aminimum value. That is, min{P_CMAX(I,k)−P_alloc_xeNB(k), P_CMAX(I,k+1)−P_alloc_xeNB(k+1)} may be used. Next, one detailed example of amethod for the UE to transmit the power in the power limit situationwill be described. In the embodiment, the first eNodeB will be describedas the MeNB and the eNodeB2 will be described as the SeNB for easydescription.

As a first example, the minimum power or more is configured with respectto all or some of the uplink channels transmitted to the SeNB. Herein,the uplink channel may correspond to {Set 0, Set 1, Set 2, Set 3}, {Set0, Set 1, Set 2}, or {Set 0, Set 1}. In this case, the power scaling maybe performed in order to guarantee the minimum power even in the uplinkchannel having the high priority. As one example, even when the priorityof the PUSCH including the UCI to be transmitted to the MeNB isconfigured to be higher than the priority of the PUCCH including theHARQ-ACK to be transmitted to the SeNB, the UE may perform the powerscaling with respect to the uplink channel of the MeNB in order toguarantee the minimum power of the SeNB in the power limit situation.

As a second example, the minimum power or more is configured withrespect to all or some of the uplink channels to be transmitted to theSeNB. Herein, the uplink channel may correspond to {Set 0, Set 1, Set 2,Set 3}, {Set 0, Set 1, Set 2}, or {Set 0, Set 1}. For example, when theuplink channels transmitted to the MeNB are the PRACH, the PUCCH, thePUSCH including the UCI, and the PUSCH, the minimum transmission powerfor the SeNB may not be guaranteed. However, herein, the SPS PUSCH maybe excluded. As one example, when the UE intends to transmit the PUCCHto the SeNB and transmits the PUSCH including the UCI to the MeNB, theuplink channel for the SeNB may not be transmitted or the transmissionpower may be configured to be lower than the minimum transmission power.

As a third example, the transmission power of the uplink channel to theSeNB may be continuously reserved as the minimum power or more. Herein,the minimum power may be configured for each specific channel. Thespecific channel may be correspond to {Set 0, Set 1, Set 2, Set 3}, {Set0, Set 1, Set 2}, or {Set 0, Set 1}. In this case, even when thetransmission of the uplink channel to the SeNB is not actuallyperformed, the power which may be maximally used by the MeNB does notexceed a limited value of the minimum power in the Pcmax.

As a subsequent operation, according to the priority rule, the UE mayperform power scaling/dropping.

3. Case where Minimum UE Transmission Power for First eNodeB and SecondeNodeB is Simultaneously Configured

It may be considered that the minimum UE transmission power isconfigured with respect to both eNodeBs by a method for protectingcoverage of the MeNB and maximizing spectral efficiency by the SeNB inthe dual connectivity. When a value of total power actually scheduled byeach eNodeB is smaller than the minimum UE transmission power, thecorresponding value may be substituted with the value of thecorresponding minimum UE transmission power. Herein, when the finaltransmission power (the total sum of the power for each channel) of atleast one of the MCG and the SCG is smaller than the minimum UEtransmission power P_xeNB initially configured fro each eNodeB, theresidual power (e.g., P_CMAX−P_MeNB or P_CMAX−P_SeNB) may be assigned toother cell group and in this case, the corresponding other cell groupmay assign the final transmission power with the residual power(P_CMAX-total allocated power to the other eNodeB) as the upper limit.The assigned power may be configured to maximum power which may be usedby the UE and thereafter, the power may be assigned to each channel byapplying the rule according to Rel-11. In this case, in the situation inwhich the timing is not synchronized, for example, the situation inwhich two subframes overlap with each other, the value of the powerwhich is not used throughout two subframes needs to become the minimumvalue. That is, min{P_CMAX(I,k)−P_alloc_xeNB(k), P_CMAX(I,k+1)−P_alloc_xeNB(k+1)} may be used. Next, one detailed example of amethod for the UE to scale the power in the power limit situation willbe described. In this case, it may be assumed that request power foreach cell group is larger than P_xeNB. In the embodiment, the firsteNodeB will be described as the MeNB and the eNodeB2 will be describedas the SeNB for easy description.

As a first example, the power of the uplink channel for each eNodeB isconfigured as large as the configured minimum transmission power.Thereafter, the residual power (that is, the value obtained bysubtracting the sum of the respective minimum power from Pcmax) isevenly assigned to the MeNB and the SeNB. The assignment may includereserving the corresponding power when there is no uplink transmission.

As a second example, the power of the uplink channel for each eNodeB isconfigured as large as the configured minimum UE transmission power.Thereafter, the residual power (that is, the value obtained bysubtracting the sum of the respective minimum power from Pcmax) isunevenly assigned to the MeNB and the SeNB according to a ratio of theconfigured minimum power. The assignment may include reserving thecorresponding power when there is no uplink transmission. As oneexample, when the minimum power for the MeNB is configured to be twicelarger than the minimum power for the SeNB, it may be considered thatthe residual power is additionally assigned to the MeNB double even atthe time of assigning the residual power.

As a third example, the power of the uplink channel for each eNodeB isconfigured as large as the configured minimum UE transmission power.Thereafter, in respect to the residual power (that is, the valueobtained by subtracting the sum of the respective minimum power fromPcmax), the power is additionally assigned to the eNodeB or cell havingthe higher priority according to the priority rule.

Herein, when final configured power of some channels (e.g., the PUCCHand/or PUSCH including the HARQ-ACK) is smaller than P_xeNB (the minimumUE transmission power configured for each cell group) or power initiallyscheduled by a TPC, and the like and the minimum value of P_CMAX,c, itmay be considered that dropping the transmission of the correspondingchannel may be additionally considered. In a subsequent operation, thetotal sum of the power assigned to the channel for each cell group isfixed to the maximum power which may be used in each cell group andthereafter, the priority rule or power scaling rule according to theexisting Rel-11 may be applied. Herein, it may be assumed that a casewhere the sum of the minimum power exceeds the Pcmax does not occur, andin the case, it may be construed that the UE does not operate in thedual connectivity mode. Alternatively, when the sum of the minimum powerexceeds the Pcmax, the UE may change the minimum power to P_MeNB=P_MeNB;P_SeNB=P_CMAX−P_MeNB.

The minimum UE transmit power may be a form in which the valueconfigured in the eNodeB is used by the UE as it is, and may be a formin which the value is updated by using the value configured in thehigher layer for each subframe and the TPC. The following description isan example of a method of configuring the minimum UE transmit power foreach channel (PUSCH, PUCCH).PUSCH:P _(PUSCH_MIN,c)(i)=min{P _(CMAX,c)(i),P_(O_PUSCH,c)(1)+α_(c)(1)·PL _(c) +f _(c)(i)}[dBm]PUCCH:P _(PUCCH_MIN,c)(i)=min{P _(CMAX,c)(i),P _(0_PUCCH,c) +PL _(c)+g(i)}[dBm]  [Equation 1]

Where, P_(0_PUCCH,c) is a high layer signal configured only in the PCellin the existing Rel-11, but may be added even in the cell correspondingto the SeNB like the pSCell in the Dual connectivity. As another method,a method of configuring an additional reference format to the UE foreach channel may be considered. As an example, the reference format forthe PUCCH may be configured to the bit number of HARQ-ACK according tothe number of configured cells to the corresponding eNodeB in the PUCCHformat 3. Herein, the configured cell is a cell by the MeNB or the SeNB.

In the present disclosure, {circumflex over (P)} is referred to as alinear value of the corresponding parameter P.

When the minimum guaranteed UE transmit power is designated to the eNB1and/or eNB2, each eNB first allocates the UE transmit power to eachconfigured power value or less, and then when the remaining power isallocated, each eNB may transmit the plurality of UL channels. In thesame CG, the plurality of UL channels may determine the power allocationsequence according to the Rel-11 priority rule. In addition, theremaining power may be allocated according to the priority rule selectedaccording to the first disclosure. When the minimum guaranteed UEtransmit power is indicated as the P_MeNB, P_SeNB for each CG, in onlythe channel in which the power of the channel transmitted to each CGexceeds the P_MeNB or the P_SeNB, the remaining power is allocated. Forexample, it is assumed that the PUCCH and the PUSCH are transmitted tothe MCG and the PUCCH and the PUSCH are transmitted to even the SCG. Inthis case, in the case of MCG PUCCH, when the allocated power is smallerthan the P_MeNB, and in the case of the SCG PUCCH, when the allocatedpower is larger than the P_SeNB, the remaining power (in terms of thelinear scale, P_CMAX−P_MeNB−P_SeNB in the embodiment) is allocatedaccording to the priority rule, it is performed in the MCG PUSCH, SCGPUCCH, SCG PUSCH

In the embodiment described below, for convenience of description, it isassumed that the UL channels to allocate the remaining power have thepriority in order of CH1>CH2>CH3>CH4>CH5=CH6. In other words, it isassumed that the channels are arranged according to the priority ruleand thereafter, the remaining power is allocated the in the order of thearranged channels. Further, it is assumed that CH1, CH3, and CH5 aretransmitted to the MCG and CH2, CH4, and CH6 are transmitted to the SCG.

First, the power of CH1 is configured. The power of the CH1 is thescheduled power constituted by a combination of pathloss, high layersignaled value, TPC command, and the like and a value allocated in theP_MeNB (denoted by {tilde over (P)}_(CH1,c)(i), a power value allocatedto the corresponding channel when allocating the P_xeNB to each CG) ofthe allocates a limited value and a minimum value between the remainingpower to the CH1. Herein, {circumflex over (P)}_(CH1,c)(i) represents anallocated amount when some channels are allocated when allocating thepower to each CG by P_MeNB or P_SeNB in the early stages, andaccordingly, without the P_MeNB or P_SeNB, the corresponding value isset to 0 and when the corresponding channel exceeds the P_MeNB or P_SeNBvalue, the corresponding value is designated to P_MeNB or P_SeNB.

First, {circumflex over (P)}_(xeNB)(i)=min{{circumflex over (P)}_(xeNB),{circumflex over (P)}_(alloc_by_TPC)} is allocated for each eNB beforeallocating the power for each CH. Herein, P_alloc_by_TPC is a sum of allUL schedules (for the target eNB) other than PRACH and SRS allocated tothe TPC. That is, the P_alloc_by_TPC means the sum of all the scheduledUL power. Accordingly, if there is no schedule or the power location islower than P_xeNB, the smaller power may be set. The setting may beapplied when the UE notifies information on subframe at the later timingof another eNB.

When the CH1 is the PUCCH as an example, the power setting equation isas follows.

                                 [Equation  2]${{\hat{P}}_{{CH}\; 1}(i)} = {{\min\;\begin{Bmatrix}{{{{\hat{P}}_{CMAX}(i)} - {{\hat{P}}_{MeNB}(i)} - {{\hat{P}}_{SeNB}(i)}},} \\{{{\hat{P}}_{{PUCCH},{PCell}}(i)} - {{\hat{\overset{\sim}{P}}}_{{{CH}\; 1},c}(i)}}\end{Bmatrix}} + {{\hat{\overset{\sim}{P}}}_{{{CH}\; 1},c}(i)}}$

Herein, P_(PUCCH,PCell)(i) is scheduling power for the PUCCHcorresponding to the MCG in SF I and may be a value set according to theexisting Rel-11, and has an upper limit of P_CMAX,c. The followingequation is expressed.

                                 [Equation  3]${P_{PUCCH}(i)} = {\min\;\begin{Bmatrix}{{P_{{CMAX},c}(i)},} \\\begin{matrix}{P_{0{\_ PUCCH}} + {PL}_{c} + {h\left( {n_{CQI},{n_{{HARQ},}n_{SR}}} \right)} +} \\{{\Delta_{F\_ PUCCH}(F)} + {\Delta_{TxD}\left( F^{\prime} \right)} + {g(i)}}\end{matrix}\end{Bmatrix}}$

Next, the power of the CH 2 is configured. The power of the CH 2 mayconfigure a value excepting the power of CH1 from the remaining power tothe upper limit. Similarly, the power of the CH2 is the scheduled powerhaving the upper limit of P_CMAX,c constituted by a combination ofpathloss, high layer signaled value, TPC command, and the like and avalue allocated in the P_MeNB (denoted by {tilde over (P)}_(CH1,c)(i), apower value allocated to the corresponding channel when allocating theP_xeNB to each CG) of the allocates a limited value and a minimum valuebetween the remaining power to the CH2. When the CH2 is the PUCCH as anexample, the corresponding setting equation is as follows.

                                     [Equation  4]${{\hat{P}}_{{CH}\; 2}(i)} = {{\min\;\begin{Bmatrix}{{\min\left( {{{{\hat{P}}_{CMAX}(i)} - {{\hat{P}}_{MeNB}(i)} - {{\hat{P}}_{SeNB}(i)} - {{\hat{P}}_{{CH}\; 1}(i)}},0} \right)},} \\{{{\hat{P}}_{{PUCCH},{pSCell}}(i)} - {{\hat{\overset{\sim}{P}}}_{{{CH}\; 2},c}(i)}}\end{Bmatrix}} + {{\hat{\overset{\sim}{P}}}_{{{CH}\; 2},c}(i)}}$

Herein, P_(PUCCH,pSCell)(i) is scheduling power for the PUCCHcorresponding to the MCG in SF I and may be a value set according to theexisting Rel-11, and has an upper limit of P_CMAX,c.

Next, the power of the CH 3 is configured. In the same manner, the powerof the CH 3 may configure a value excepting the power of CH1 from theremaining power as the upper limit. In the scheduled power having theupper limit of P_CMAX,c, a value allocated in the P_MeNB (denoted by{tilde over (P)}_(CH1,c)(i), a power value allocated to thecorresponding channel when allocating the P_xeNB to each CG) is notapplied to the embodiment. When the CH3 is the PUSCH with UCI as anexample, the corresponding setting equation is as follows.

                                     [Equation  5]${{\hat{P}}_{{CH}\; 3}(i)} = {{\min\;\begin{Bmatrix}{{\min\left( {{{{\hat{P}}_{CMAX}(i)} - {{\hat{P}}_{MeNB}(i)} - {{\hat{P}}_{SeNB}(i)} - {{\hat{P}}_{{CH}\; 1}(i)} - {{\hat{P}}_{{CH}\; 2}(i)}},0} \right)},} \\{{{\hat{P}}_{{PUSCH},{MCG\_ j}}(i)} - {{\hat{\overset{\sim}{P}}}_{{{CH}\; 3},c}(i)}}\end{Bmatrix}} + {{\hat{\overset{\sim}{P}}}_{{{CH}\; 3},c}(i)}}$

Herein, P_(PUCCH,pSCell)(i) is scheduling power for the PUCCHcorresponding to the MCG in SF i, may be a value set according to theexisting Rel-11, has an upper limit of P_CMAX,c or 10 log₁₀({circumflexover (P)}_(CMAX,c)(i)−{circumflex over (P)}_(PUCCH)(i)) according towhether the PUCCH and PUSCH are simultaneously transmitted in thecorresponding serving cell. When the PUCCH and PUSCH are notsimultaneously transmitted, P_(PUCCH,pSCell)(i) is expressed by equation3-1 and when PUCCH and PUSCH are simultaneously transmitted,P_(PUCCH,pSCell)(i) is expressed by Equation 6.

                                 [Equation  6]${P_{{PUSCH},c}(i)} = {\min\;{\begin{Bmatrix}{{P_{{CMAX},c}(i)},} \\\begin{matrix}{{10\;{\log_{10}\left( {M_{{PUSCH},c}(i)} \right)}} + {P_{{O\_ PUSCH},c}(j)} +} \\{{{\alpha_{c}(j)} \cdot {PL}_{c}} + {\Delta_{{TF},c}(i)} + {f_{c}(i)}}\end{matrix}\end{Bmatrix}\mspace{574mu}\left\lbrack {{Equation}\mspace{14mu} 7} \right\rbrack}}$${P_{{PUSCH},c}(i)} = {\min\;\begin{Bmatrix}{{10\;{\log_{10}\left( {{{\hat{P}}_{{CMAX},c}(i)} - {{\hat{P}}_{PUCCH}(i)}} \right)}},} \\\begin{matrix}{{10\;{\log_{10}\left( {M_{{PUSCH},c}(i)} \right)}} + {P_{{O\_ PUSCH},c}(j)} +} \\{{{\alpha_{c}(j)} \cdot {PL}_{c}} + {\Delta_{{TF},c}(i)} + {f_{c}(i)}}\end{matrix}\end{Bmatrix}}$

Alternatively, only in the dual connectivity mode UE,P_(PUCCH,pSCell)(i) may be set by Equation 6.

Next, the power of the CH 4 is configured. In the same manner, the powerof the CH 4 may configure a value excepting the power of the channelhaving high priority from the remaining power as the upper limit. In thescheduled power having the upper limit of P_CMAX,c, a value allocated inthe P_MeNB (denoted by {tilde over (P)}_(CH1,c)(i), a power valueallocated to the corresponding channel when allocating the P_xeNB toeach CG) is not applied to the embodiment. When the CH4 is the PUSCHwith UCI as an example, the corresponding setting equation is asfollows.

                                 [Equation  8]${{\hat{P}}_{{CH}\; 4}(i)} = {{\min\;\begin{Bmatrix}{\min\left( {{{\hat{P}}_{CMAX}(i)} - {{\hat{P}}_{MeNB}(i)} - {{\hat{P}}_{SeNB}(i)} -} \right.} \\{\left. \mspace{20mu}{{{{\hat{P}}_{{CH}\; 1}(i)} - {{\hat{P}}_{{CH}\; 2}(i)} - {{\hat{P}}_{{CH}\; 3}(i)}},0} \right),} \\{{{\hat{P}}_{{PUSCH},{SCG\_ j}}(i)} - {{\hat{\overset{\sim}{P}}}_{{{CH}\; 4},c}(i)}}\end{Bmatrix}} + {{\hat{\overset{\sim}{P}}}_{{{CH}\; 4},c}(i)}}$

Herein, P_(PUCCH,pSCell)(i) is scheduling power for the PUCCHcorresponding to the MCG in SF i, may be a value set according to theexisting Rel-11, has an upper limit of P_CMAX,c or 10 log₁₀({circumflexover (P)}_(CMAX,c)(i)−{circumflex over (P)}_(PUCCH)(i)) according towhether the PUCCH and PUSCH are simultaneously transmitted in thecorresponding serving cell. When the PUCCH and PUSCH are notsimultaneously transmitted, P_(PUCCH,pSCell)(i) may be expressed byEquation 6 and when PUCCH and PUSCH are simultaneously transmitted,P_(PUCCH,pSCell)(i) may be expressed by Equation 7. Alternatively, onlyin the dual connectivity mode UE, P_(PUCCH,pSCell)(i) may be set byEquation 6.

Next, it is assumed that CH5 and CH6 have the same priority and may beincluded in the same CG unlike the embodiment. For example, when the CH5and CH6 are the PUSCH without UCI as an example, the corresponding powersetting equation is as follows.

                                  [Equation  9]${\sum\limits_{{c \neq {MCG\_ j}},{SCG\_ j}}{{w(i)} \cdot {{\hat{P}}_{{PUSCH},c}(i)}}} \leq {\min\;\left( {{{{\hat{P}}_{CMAX}(i)} - {{\hat{P}}_{MeNB}(i)} - {{\hat{P}}_{SeNB}(i)} - {{\hat{P}}_{{CH}\; 1}(i)} - {{\hat{P}}_{{CH}\; 2}(i)} - {{\hat{P}}_{{CH}\; 3}(i)} - {{\hat{P}}_{{CH}\; 4}(i)}},0} \right)}$

Herein, P_(PUCCH,pSCell)(i) is scheduling power for the PUCCHcorresponding to the MCG in SF i, may be a value set according to theexisting Rel-11, has an upper limit of P_CMAX,c or 10 log₁₀({circumflexover (P)}_(CMAX,c)(i)−{circumflex over (P)}_(PUCCH)(i)) according towhether the PUCCH and PUSCH are simultaneously transmitted in thecorresponding serving cell. When the PUCCH and PUSCH are notsimultaneously transmitted, P_(PUCCH,pSCell)(i) may be expressed byEquation 6 and when PUCCH and PUSCH are simultaneously transmittedP_(PUCCH,pSCell)(i) may be expressed by Equation 7. Alternatively, onlyin the dual connectivity mode UE, P_(PUCCH,pSCell)(i) may be set byEquation 6.

In Equation 9, when the priority for the MCG of the PUSCH without UCI ishigher than the priority for the SCG, the power may also be configuredin the same manner as the CH2, CH3, CH4.

In the embodiment, it may be assumed that when some channels are nottransmitted, the value for the corresponding CH is not considered in theequation. Further, according to the priority rule configuration, thechannel designated by each CH may be changed and in this case, thespirit of the present invention may be extended and applied.

In the example, like the CH1 and CH2, when some power is included in theallocation of P_MeNB or P_SeNB, if the CH1 and CH2 are the PUSCH withoutUCI, the power scaling method may be constituted as a detailed example.

As a first example, the power scaling is performed at the time ofallocating the remaining power after allocating P_MeNB or P_SeNB.

As a second example, the power scaling is performed with respect to theentire allocation power by considering the P_MeNB or P_SeNB allocatedpart.

Herein, the sum of the P_MeNB and the P_SeNB may be configured to belarger than P_CMAX, and in this case, at the time of applying the actualpower allocation, the minimum guaranteed power needs to be recontrolled.Next, when the sum of the P_MeNB and the P_SeNB is larger than P_CMAX, adetailed example of the power allocation method is as follows.

As a first example, the sum is set to P_CMAX or less through unequal orequal scaling. Thereafter, the UE may perform the corresponding powerallocation procedure.

As a second example, the value of the P_MeNB is maintained as it is andthe value of the P_SeNB is recontrolled to P_CMAX-P_MeNB or less.Thereafter, the UE may perform the corresponding power allocationprocedure.

As a third example, the value of the P_SeNB is maintained as it is andthe value of the P_MeNB is recontrolled to P_CMAX-P_SeNB or less.Thereafter, the UE may perform the corresponding power allocationprocedure.

As a fourth example, a maintained value of the P_MeNB and the P_SeNB isset through the higher layer for the UE.

The P_MeNB and the P_SeNB may be referred to as a value set in the MeNBin the early stages, and in the power allocation process, may bereferred to as a value after calculating {circumflex over(P)}_(xeNB)(i)=min{{circumflex over (P)}_(xeNB), {circumflex over(P)}_(alloc_by_TPC)}.

Generally, the equations may be deployed as follows.{circumflex over (P)} _(Reserved_SeNB(MeNB))(i)=min{{circumflex over(P)} _(SeNB)(i),Σ{circumflex over (P)}_(alloc_by_TPC on non-SRS/non-PRACH UL Tx to SeNB)(i)}  [Equation 10]{circumflex over (P)} _(Reserved_SeNB(SeNB))(i)=0  [Equation 11]{circumflex over (P)} _(Reserved_MeNB(SeNB))(i)=min{{circumflex over(P)} _(MeNB)(i),Σ{circumflex over (P)}_(alloc_by_TPC on non-SRS/non-PRACH UL Tx to MeNB)(i)}  [Equation 12](1){circumflex over (P)} _(Reserved_MeNB(MeNB))(i)=0  [Equation 13]

In the following embodiment, the power allocation to the PUCCH/PUSCHwill be described.

First, the CH1 having the first priority will be described.

{circumflex over (P)}_(CH1) ^(r)(i) means the requested power by TPC andupper bounded by P_CMAX,c for first priority channel CH1.

First, if it is to MeNB, {circumflex over (P)}_(reserved)(i)={circumflexover (P)}_(Reserved_SeNB(MeNB))(i)

If it is to SeNB, {circumflex over (P)}_(reserved)(i)={circumflex over(P)}_(Reserved_MeNB(SeNB))(i)

${{\hat{P}}_{{CH}\; 1}(i)} = {\min\;\begin{Bmatrix}{{{\hat{P}}_{CMAX}(i)} - {{\hat{P}}_{reserved}(i)}} \\{{\hat{P}}_{{CH}\; 1}^{r}(i)}\end{Bmatrix}}$

If the transmission is to MeNB,{circumflex over (P)} _(Reserved_SeNB(MeNB))(i)=max{{circumflex over(P)} _(Reserved_SeNB(MeNB))(i)−{circumflex over (P)} _(CH1)(i),0}

If the transmission is to SeNB,{circumflex over (P)} _(Reserved_MeNB(SeNB))(i)=max{{circumflex over(P)} _(Reserved_MeNB(SeNB))(i)−{circumflex over (P)} _(CH1)(i),0}]

For the second priority UL transmission CH2

If it is to MeNB, {circumflex over (P)}_(reserved)(i)={circumflex over(P)}_(Reserved_SeNB(MeNB))(i)

If it is to SeNB, {circumflex over (P)}_(reserved)(i)={circumflex over(P)}_(Reserved_MeNB(SeNB))(i)

${{\hat{P}}_{{CH}\; 2}(i)} = {\min\;\begin{Bmatrix}{{{\hat{P}}_{CMAX}(i)} - {{\hat{P}}_{reserved}(i)} - {{\hat{P}}_{{CH}\; 1}(i)}} \\{{\hat{P}}_{{CH}\; 2}^{r}(i)}\end{Bmatrix}}$

If the transmission is to MeNB,{circumflex over (P)} _(Reserved_SeNB(MeNB))(i)=max{{circumflex over(P)} _(Reserved_SeNB(MeNB))(i)−{circumflex over (P)} _(CH2)(i),0}

If the transmission is to SeNB,{circumflex over (P)} _(Reserved_MeNB(SeNB))(i)=max{{circumflex over(P)} _(Reserved_MeNB(SeNB))(i)−{circumflex over (P)} _(CH2)(i),0}

For m-th priority UL transmission CHm

If it is to MeNB, {circumflex over (P)}_(reserved)(i)={circumflex over(P)}_(Reserved_SeNB(MeNB))(i)

If it is to SeNB, {circumflex over (P)}_(reserved)(i)={circumflex over(P)}_(Reserved_MeNB(SeNB))(i)

${{\hat{P}}_{CHm}(i)} = {\min\;\begin{Bmatrix}{{{\hat{P}}_{CMAX}(i)} - {{\hat{P}}_{reserved}(i)} - {\sum\limits_{k = 1}^{m - 1}{{\hat{P}}_{CHk}(i)}}} \\{{\hat{P}}_{CHm}^{r}(i)}\end{Bmatrix}}$

If the transmission is to MeNB,{circumflex over (P)} _(Reserved_SeNB(MeNB))(i)=max{{circumflex over(P)} _(Reserved_SeNB(MeNB))(i)−{circumflex over (P)} _(CHm)(i),0}

If the transmission is to SeNB,{circumflex over (P)} _(Reserved_MeNB(SeNB))(i)=max{{circumflex over(P)} _(Reserved_MeNB(SeNB))(i)−{circumflex over (P)} _(CHm)(i),0}

Once all power is allocated among channels, the total power for each CGis computed by summation of all power of channels transmitted to eachCG. For example, if MCG has CH1, CH3, CH5 then, the summation of{circumflex over (P)}_(CH1)(i), {circumflex over (P)}_(CH3)(i),{circumflex over (P)}_(CH5)(i), will be used for the allocated power toMCG.

In terms of handling priority, if there is more than one PUSCH in eachCG, it will be treated as if one PUSCH with power is setting as the sumof all PUSCH transmissions within each CG. Herein, the PUSCH may notinclude the UCI. Alternatively, if there are one or more PUSCHs in eachCG, it can be treated separated for each PUSCH with its own configuredpower. In this case, power for some PUSCH with high priority would notbe scaled while some

PUSCH with low priority may be dropped or power scaled. It can beconsidered that PUSCH in MCG has higher priority compared to PUSCH inSCG. Another method is that priority for power setting on PUSCH (withoutUCI) is based on (1) cell index, (2) the number of PUSCH in each CG, or(3) total payload size. It can be considered that PUSCH 1 on MCG>PUSCH 1on SCG>PUSCH 2 on MCG>PUSCH 2 on SCG>, . . . . Once the power isallocated, Rel-11 power scaling can be applied within a CG. Thus, powerscaling can be occurred within a CG once the power allocation iscompleted.

As another example, it may be considered that when the power of thePUCCH and the PUSCH with HARQ-ACK is determined, the remaining power isevenly scaled to all of the PUSCHs according to a weight. However, whenthe minimum power per CG is configured, in order to guarantee the power,the minimum power per CG may be applied only to the remaining power.

Meanwhile, for example, assuming the priority is PUCCH=PUSCH-HARQ-ACK onMCG>PUCCH=PUSCH-HARQ-ACK on SCG>PUSCH on MCG>PUSCH on SCG, the power isdetermined as follows.

The power for the PUCCH including the HARQ-ACK or the PUSCH includingthe HARQ-ACK for the MCG may be determined as follows.

$\begin{matrix}{{{\hat{P}}_{{PUCCH},{MeNB}}(i)} = {\min\;\begin{Bmatrix}{{{\hat{P}}_{CMAX}(i)} - {\hat{P}}_{reserved}} \\{{\hat{P}}_{{PUCCH},{MeNB}}^{r}(i)}\end{Bmatrix}}} & \left\lbrack {{Equation}\mspace{14mu} 14} \right\rbrack\end{matrix}$

Where Preserved is calculated for the CH1 and {circumflex over (P)}^(r)_(PUCCH,MeNB)(i) is calculated as described above.

For PUCCH-HARQ-ACK or PUSCH-HARQ-ACK on SCG, the power may be same toCH2 if PUCCH-HARQ-ACK or PUSCH-HARQ-ACK on MCG is transmitted.Otherwise, PUCCH-HARQ-ACK (or PUSCH-HARQ-ACK) on MCG power may be zero.

                                [Equation  15]${{\hat{P}}_{{PUCCH},\;{SeNB}}(i)} = {\min\;\begin{Bmatrix}{{{\hat{P}}_{CMAX}(i)} - P_{reserved} - {{\hat{P}}_{{PUCCH},{MeNB}}(i)}} \\{{\hat{P}}_{{PUCCH},\;{SeNB}}^{r}(i)}\end{Bmatrix}}$

The PUSCH for the MCG is as follows.

                                     [Equation  16]${{\hat{P}}_{{PUSCH},\;{MeNB}}(i)} = {\min\;\begin{Bmatrix}{{{\hat{P}}_{CMAX}(i)} - P_{reserved} - {{\hat{P}}_{{PUCCH},\;{MeNB}}(i)} - {{\hat{P}}_{{PUCCH},\;{SeNB}}(i)}} \\{{\hat{P}}_{{PUSCH},\;{MeNB}}^{r}(i)}\end{Bmatrix}}$

The PUSCH for the SCG is as follows.

                                [Equation  17]${{\hat{P}}_{{PUSCH},\;{SeNB}}(i)} = {\min\;\begin{Bmatrix}\begin{matrix}{{{\hat{P}}_{CMAX}(i)} - P_{reserved} - {{\hat{P}}_{{PUCCH},\;{MeNB}}(i)} -} \\{{{\hat{P}}_{{PUCCH},\;{SeNB}}(i)} - {{\hat{P}}_{{PUSCH},\;{MeNB}}(i)}}\end{matrix} \\{{\hat{P}}_{{PUSCH},\;{SeNB}}^{r}(i)}\end{Bmatrix}}$

Preserved is updated when the power is allocated for each channelRemoving the allocated power from the allocated power is a basicoperation. Accordingly, it may be meant how much the power is allocated.

In summary, the above options may be summarized in the following twocases.

Case 1:

If the total requested power per CG does not exceed P_xeNB, thenallocate the power.

If the total requested power per CG exceeds P_xeNB, then,

for the remaining power P_CMAX−P_SeNB-P_MeNB, follow priority rule basedon UCI type across CGs and allocate the remaining power in order.

For each CG, apply Rel-11 priority rule with UE total power per CG isbounded by the sum of total allocated power with P_xeNB.

Case 2:

PRACH to PCell is transmitted with the requested power.

PRACH to SCell is dropped if it collides with PRACH to PCell in a powerlimited case.

If not, PRACH to SCell is transmitted with the requested powerotherwise.

PUCCH on cell group x is transmitted with the power=min {PPUCCH,P_CMAX−P_alloc_xeNB}

Where, P_alloc_xeNB is the summation of the allocated power to xeNBaccording to priority rule and min {P_xeNB, total requested power on xCGby TPC}

PUSCH with UCI on cell group x is transmitted with power=min {PPUSCH,P_CMAX−P_alloc_xeNB−PPUCCH}

PUSCH without UCI on cell group x is transmitted withpower=P_CMAX−P_alloc_xeNB−PPUCCH−PPUSCH w/UCI}=sum {w(i)*PPUSCH}

The above parameters relevant to UE Tx power are in linear scale.

Meanwhile, in the case of the SRS, when there is power allocated to thecell group to which the SRS is to be transmitted or reserved power, theRel-11 rule may be applied by using the corresponding allocated orreserved power instead of P_CMAX. Herein, the allocated power or thereserved power may be configured as (i) the minimum power (e.g., P_MeNBor P_SeNB) configured for the corresponding cell group, (ii) the sum ofthe minimum power configured for the corresponding cell group and theremaining power (the total sum of power used by other channels havingthe higher priority than the corresponding SRS except for P_MeNB andP_SeNB), or (iii) a difference of the total sum of power used by otherchannels having the higher priority than the corresponding SRS inP_CMAX. In more detail, it may be considered that the SRS is transmittedonly in a specific situation such as (i) a case in which only the SRS ispresent in the cell group, (ii) a case in which only one SRS is present,(iii), a case in which only the periodic SRS is present, or (iv) a casein which the aperiodic SRS is present. In this case, the SRS may bepower-scaled.

<Third Disclosure of Present Specification>

The third disclosure of the present specification proposes a method forsolving a power control in the time synchronization is not matchedbetween the MCG and the SCG.

In the dual connectivity situation, it may be assumed that an interfaceof the subframe between two eNodeBs is not matched in timing.

FIGS. 11a to 11e illustrate one example for power control in a situationin which subframes are asynchronous among eNodeBs.

Referring to the illustrated examples, it may be considered that asubframe I of the first eNodeB overlaps with a subframe k and a subframek+1 of the second eNodeB. In this case, it may be considered that anoverlapping area is divided into many parts to perform power control andpower scaling. For example, Pcmax and Pcmax,c may be set for eachoverlapping part (hereinafter, setting for subframe (i, k) and subframe(i, k+1)) and even during power scaling, the Pcmax and Pcmax,c arecalculated according to the above method for each overlapping part andthen the final power for each subframe may be set to the minimum valueof the power for the overlapping part corresponding to the subframe. Asan example, when the power for the subframe i of the first eNodeB iscalculated, a subframe k of the second eNodeB overlapping with theeNodeB subframe i sets the power(i, k) according to the power scalingand the subframe k+1 of the second eNodeB calculates power(i, k+1)according to the power scaling, and then the power for the subframe i ofthe first eNodeB may be set to the minimum value of power(i, k) andpower(i, k+1). In the second disclosure of the present specification, asan example, when CH1 corresponds to the MCG and CH2 corresponds to theSCG, it may be considered that the power of the CH2 is set by thefollowing Equation.

                                [Equation  18]${{\hat{P}}_{{CH}\; 2}\left( {i;k} \right)} = {\min\;\begin{Bmatrix}{{{\hat{P}}_{CMAX}(i)} - {{\hat{P}}_{reserved}(k)} - {{\hat{P}}_{{CH}\; 1}(k)}} \\{{\hat{P}}_{{CH}\; 2}^{r}(i)}\end{Bmatrix}}$${{\hat{P}}_{{CH}\; 2}\left( {i;{k + 1}} \right)} = {\min\;\begin{Bmatrix}{{{\hat{P}}_{CMAX}(i)} - {{\hat{P}}_{reserved}\left( {k + 1} \right)} - {{\hat{P}}_{{CH}\; 1}\left( {k + 1} \right)}} \\{{\hat{P}}_{{CH}\; 2}^{r}(i)}\end{Bmatrix}}$ P̂_(CH 2)(i) = min  {P̂_(CH 2)(i; k), P̂_(CH 2)(i; k + 1)}

In the above description, when each eNodeB sets the power for thecorresponding uplink channel, in order to obtain a TPC command foranother eNodeB, it is required to detect (E)PDCCH and the like. In somecases, power information for another eNodeB may not be perfect due tothe processing time shortage, and in this case, like the aforementionedmethod, it is not efficient to apply the priority rule considering allof the overlapped parts described above. In order to solve the problem,the network determines whether look-ahead is enabled or disabled throughthe higher layer.

Due to the processing time shortage, even though the PUCCH/PUSCH do notuse the power setting information of another eNodeB (the look-ahead isdisabled), exceptionally, the PRACH and/or SRS may be configured to usethe power setting information for another eNodeB. As an example, in thecase of the PRACH, an environment of configuring whether the PRACH istransmitted to the UE terminal may be considered, and in the case of thePRACH transmission by the PDCCH order, the PDCCH order includes 6subframes from the received time to be transmitted hereinafter, and thusthe processing time may be sufficient. Further, even when the SRS isfirst transmitted and the channel having higher priority is transmittedto another eNodeB, the SRS is transmitted only to the final OFDM symbolin the subframe and thus the processing time is sufficient.

Further, when a high priority is given in a cell group corresponding toearlier transmission when performing power control between differentcell groups in the SRS transmission, the SRS is transmitted only in thefinal OFDM symbol and thus, it may be considered that the power is setunlike the PUCCH/PUSCH. More particular examples are as follows.

As a first example, the SRS configures a high priority to the earliertransmitted channel based on the transmitted subframe. For example, whenthe subframe including the SRS is earlier than the subframe includingthe channel transmitted from another cell group, the priority for theSRS is configured to be high and the power may be first allocated. Thechannel may exclude the SRS and in this case, it may be assumed that thepriority is the same between the SRSs even though the cell groups aredifferent. Further, even in the PRACH, exceptionally, it may beconsidered that the higher priority is continuously given to the PRACHthan the SRS. It may be limited that the PRACH is transmitted by thePDCCH order. For this reason, it may be efficient when the power controlis performed and the SRS power setting is performed at the same time asanother channel such as PUCCH/PUSCH.

As a second example, based on the time (OFDM symbol unit and the like)when the SRS is actually transmitted, a high priority is set to thefirst transmitted channel. For example, even though the subframeincluding the SRS is earlier than the subframe including the channeltransmitted from another cell group such as PUCCH/PUSCH/PRACH, when alocation where the final OFDM symbol to which the SRS is actuallytransmitted starts is latter than the transmission time of thePUCCH/PUSCH/PRACH in another cell group, the PUCCH/PUSCH/PRACH and thelike transmitted from another cell is recognized as the earliertransmitted channel and configures a high priority. Similarly, at theactual transmission time, when the SRS is first transmitted, it may beconsidered that the SRS is configured to the higher priority than thechannels in another group. The channel may exclude the SRS and in thiscase, it may be assumed that the priority is the same between the SRSseven though the cell groups are different. Further, even in the PRACH,exceptionally, it may be considered that the higher priority iscontinuously given to the PRACH than the SRS. It may be limited that thePRACH is transmitted by the PDCCH order. The method may be efficientwhen the power setting for the SRS is performed at an independent timefrom the PUCCH/PUSCH.

On the other hand, when the PRACHs transmitted from the MCG and the SCGare partially overlapped, for example, a case where the PRACHtransmitted to the MCG collides at the later location of the PRACHhaving a 3-subframe length or a case where the processing time isinsufficient according to implementation during SRS transmission mayoccur. Even in this case, the power may be first allocated to the PRACHtransmitted to the MCG or the PCell, and the SRS needs to be configuredto ensure the power of the channel of another cell group having highpriority overlapping at the later time.

For example, the PRACH limits the UL transmit power of another eNodeBwith respect to all or some PRACH resources (the subframe which may betransmitted by the PRACH). The corresponding power may be set to theminimum UE transmit power of the corresponding cell group and set toP_CMAX−minimum UE transmit power. As an example, it may be consideredthat the SRS configures the power of the SRS to the minimum UE transmitpower of the corresponding cell group with respect to all or some SRSresources (the SF which may be transmitted by the SRS). In the case ofusing some subframe resources, the corresponding information may be apredetermined value and may be a value configured by the network throughthe higher layer.

<Fourth Disclosure of Present Specification>

In the fourth disclosure of the present specification, in a dualconnectivity situation, a method of piggybacking the UCI by the UE onthe PUSCH will be described.

In the dual connectivity situation, collision between the PUCCH and thePUSCH with UCI included in the different cell groups may occur andaccording to the situation, the power scaling may be required. Forexample, when it is considered that the power scaling occurs in thePUSCH, the transmission reliability for the UCI included in the PUSCHmay be decreased. As a result, the suitable scheduling in the eNodeBreceiving the corresponding UCI is not performed and thus packetthroughput performance experienced by the user may be deteriorated.Based on the existing 3GPP LTE Rel-12, when the PUSCH is transmitted tothe PCell, the UCI is piggybacked on the PUSCH to the PCell, and whenthe PUSCH is not transmitted to the PCell, the UCI is piggybacked on thePUSCH having the smallest cell index among the SCells transmitting thePUSCH. Next, in the case of the power-limited UE or only when an UCIpiggyback operation is configured through the high layer signal, this isa detailed example for a method of selecting the PUSCH to piggyback theUCI and may be differently configured for each UCI type.

As an example, based on a cell index, the UE selects the PUSCH of thecell having the smallest cell index. Even in this case, when the PUSCHof the PCell (alternatively, PSCell) is present, the UE selects thePUSCH of the PCell (alternatively, PSCell).

As a second example, the UE selects the PUSCH corresponding to the cellhaving the largest number of coded bits for the corresponding UCI.Alternatively, based on the subcarrier number allocated during theinitial transmission of the corresponding PUSCH, the OFDM symbol number,the transport block size for the UL-SCH, a modulation order used in thePUSCH, and the like, a PUSCH to piggyback the UCI may be selected.

As a third example, the UE selects a PUSCH having the most power for thePUSCH.

As a fourth example, the UE selects a PUSCH having the most power perunit bit for the UCI. In this case, based on the power for the PUSCH,the number of coded modulation symbols for the corresponding UCI, amodulation order, and the like, the PUSCH may be selected.

FIG. 12 is a flowchart illustrating a summarized disclosure of thepresent specification.

Referring to FIG. 12, a UE 100 determines an amount of power in a statein which a dual connectivity to a first cell group and a second cellgroup is set. Specifically, the UE determines first amount of power fora transmission of a first UCI, and determines second amount of power fora transmission of a second UCI. If the first UCI includes HARQ-ACK butthe second UCI does not include HARQ-ACK, the determination of the firstamount of the power is prioritized over the determination of the secondamount of the power.

If the first UCI includes HARQ-ACK to the first cell group and thesecond UCI include HARQ-ACK to the second cell group, the determinationof the first amount of the power may be prioritized over thedetermination of the second amount of the power.

If the first amount of the power exceeds a specific value, the firstamount of the power may be scaled down.

Meanwhile, if p_MeNB, which indicates power guaranteed for the firsteNodeB, and p_SeNB, which indicates power guaranteed for the secondeNodeB, are received using a high layer signal, p_MeNB and p_SeNB may beconsidered in the above determination.

The above determination may be performed when a first subframe on whichthe first UCI is transmitted is overlapped with a second subframe onwhich the second UCI is transmitted.

The embodiments of the present invention which has been described up tonow may be implemented through various means. For example, theembodiments of the present invention may be implemented by hardware,firmware, software, or combinations thereof. In detail, the embodimentswill be descried with reference to the drawings.

FIG. 13 is a block diagram illustrating a wireless communication systemin which a disclosure of the present specification is implemented.

The base station 200 includes a processor 201, a memory 202, and a radiofrequency (RF) unit 203. The memory 202 is connected with the processor201 to store various pieces of information for driving the processor201. The RF unit 203 is connected with the processor 201 to transmitand/or receive a radio signal. The processor 201 implements a function,a process, and/or a method which are proposed. In the aforementionedembodiment, the operation of the base station may be implemented by theprocessor 201.

UE 100 includes a processor 101, a memory 102, and an RF unit 103. Thememory 102 is connected with the processor 101 to store various piecesof information for driving the processor 101. The RF unit 103 isconnected with the processor 101 to transmit and/or receive a radiosignal. The processor 101 implements a function, a process, and/or amethod which are proposed.

The processor may include an application-specific integrated circuit(ASIC), another chip set, a logic circuit and/or a data processingapparatus. The memory may include a read-only memory (ROM), a randomaccess memory (RAM0, a flash memory, a memory card, a storage medium,and/or other storage device. The RF unit may include a baseband circuitfor processing the radio signal. When the embodiment is implemented bysoftware, the aforementioned technique may be implemented by a module (aprocess, a function, and the like) that performs the aforementionedfunction. The module may be stored in the memory and executed by theprocessor. The memory may be positioned inside or outside the processorand connected with the processor by various well-known means.

In the aforementioned exemplary system, methods have been describedbased on flowcharts as a series of steps or blocks, but the methods arenot limited to the order of the steps of the present invention and anystep may occur in a step or an order different from or simultaneously asthe aforementioned step or order. Further, it can be appreciated bythose skilled in the art that steps shown in the flowcharts are notexclusive and other steps may be included or one or more steps do notinfluence the scope of the present invention and may be deleted.

What is claimed is:
 1. A method for performing a power scaling, themethod performed by a user equipment (UE) and comprising: receiving aconfiguration of dual connectivity to a master cell group (MCG) and asecondary cell group (SCG); determining a first power for a firsttransmission toward the MCG, wherein the first power for the firsttransmission toward the MCG is determined to be less than or equal to afirst threshold configured for the MCG; determining a second power for asecond transmission toward the SCG; and scaling down the second powerfor the second transmission toward the SCG, based on (i) a total powerrelated to the MCG and the SCG exceeding a maximum total power and (ii)the first transmission toward the MCG overlapping in time with thesecond transmission toward the SCG.
 2. The method of claim 1, whereinthe second power for the second transmission toward the SCG isdetermined to be less than or equal to a second threshold configured forthe SCG.
 3. The method of claim 1, wherein the first power for the firsttransmission toward the MCG is not scaled down based on the maximumtotal power being exceeded.
 4. The method of claim 1, wherein the firsttransmission includes transmitting at least one of a first physicaluplink control channel (PUCCH) or a first physical uplink shared channel(PUSCH).
 5. The method of claim 4, wherein the at least one of the firstPUCCH or the first PUSCH includes at least one of a hybrid automaticrepeat request (HARQ) acknowledgement (ACK)/negative-acknowledgement(NACK) signal or a scheduling request (SR).
 6. The method of claim 1,wherein the second transmission includes transmitting at least one of asecond PUCCH or a second PUSCH.
 7. The method of claim 6, wherein the atleast one of the second PUCCH or the second PUSCH includes a HARQACK/NACK signal and a SR.
 8. The method of claim 1, wherein at least oneof the first power or the second power is shared across the MCG and theSCG.
 9. A user equipment (UE) configured to perform power scaling, theUE comprising: a reception unit; and a processor configured to: receive,through the reception unit, a configuration of dual connectivity to amaster cell group (MCG) and a secondary cell group (SCG); determine afirst power for a first transmission toward the MCG; wherein the firstpower for the first transmission toward the MCG is determined to be lessthan or equal to a first threshold configured for the MCG; determine asecond power for a second transmission toward the SCG; and scale downthe second power for the second transmission toward the SCG, based on(i) a total power related to the MCG and the SCG exceeding a maximumtotal power and (ii) the first transmission toward the MCG overlappingin time with the second transmission toward the SCG.
 10. The UE of claim9, wherein the second power for the second transmission toward the SCGis determined to be less than or equal to a second threshold configuredfor the SCG.
 11. The UE of claim 9, wherein the first power for thefirst transmission toward the MCG is not scaled down, based on themaximum total power being exceeded.
 12. The UE of claim 9, wherein thefirst transmission includes transmitting at least one of a firstphysical uplink control channel (PUCCH) or a first physical uplinkshared channel (PUSCH).
 13. The UE of claim 12, wherein the at least oneof the first PUCCH or the first PUSCH includes at least one of a hybridautomatic repeat request (HARQ) acknowledgement(ACK)/negative-acknowledgement (NACK) signal or a scheduling request(SR).
 14. The UE of claim 9, wherein the second transmissiontransmitting includes at least one of a second PUCCH or a second PUSCH.15. The UE of claim 14, wherein the at least one of the second PUCCH orthe second PUSCH includes a HARQ ACK/NACK signal and a SR.
 16. The UE ofclaim 9, wherein at least one of the first power or the second power isshared across the MCG and the SCG.